What size is a -010 O-ring?

An AS568 -010 is .239″ ID × .070″ W (actual, ±.005″ / ±.003″); its nominal size is 1/4 × 3/8 × 1/16″.

What does the AS568 dash number mean?

It names one O-ring size. The first digit is the cross-section series — -0xx series 1/16″ (.070″), -1xx series 3/32″ (.103″), -2xx series 1/8″ (.139″), -3xx series 3/16″ (.210″), -4xx series 1/4″ (.275″) — and the rest steps up the inside diameter.

What are the dimensions of a 214 O-ring?

AS568 -214: ID .984″ ± .010″, cross-section .139″ ± .004″.

What O-ring fits a 1/2 inch tube fitting boss?

An AS568 -908 (900 series boss gasket for 1/2″ OD tube): .644″ ID × .087″ W.

Is a 1/4 x 3/8 x 1/16 O-ring really 1/4 inch inside?

No. Those fractions are the nominal size (the name). The -010 that carries it measures .239″ inside and .070″ across the cross-section.

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O-Ring Sizes

AS568 O-ring sizes: the dash number, its nominal size, the actual inside diameter and cross-section with tolerances, and the metric equivalents.

An O-ring is a ring of rubber with a round cross-section that seals by being squeezed in a groove. Inch O-rings are sized by SAE AS568: each dash number (-010, -214) is one size, set by its inside diameter (ID) and cross-section (W); the first digit is the cross-section series. The fractions often printed with it (1/4 × 3/8 × 1/16) are the nominal size — the size’s name, not the ring’s measurement.

The letters match the table columns. Not to scale.

Jump to: -0xx · -1xx · -2xx · -3xx · -4xx · -9xx boss gaskets · mm

AS568 zero series — 1/16″ nominal cross-section
Dash	Nominal ID × OD × W	ID	W
-001	1/32 × 3/32 × 1/32	.029 ± .004	.040 ± .003
-002	3/64 × 9/64 × 3/64	.042 ± .004	.050 ± .003
-003	1/16 × 3/16 × 1/16	.056 ± .004	.060 ± .003
-004	5/64 × 13/64 × 1/16	.070 ± .005	.070 ± .003
-005	3/32 × 7/32 × 1/16	.101 ± .005	.070 ± .003
-006	1/8 × 1/4 × 1/16	.114 ± .005	.070 ± .003
-007	5/32 × 9/32 × 1/16	.145 ± .005	.070 ± .003
-008	3/16 × 5/16 × 1/16	.176 ± .005	.070 ± .003
-009	7/32 × 11/32 × 1/16	.208 ± .005	.070 ± .003
-010	1/4 × 3/8 × 1/16	.239 ± .005	.070 ± .003
-011	5/16 × 7/16 × 1/16	.301 ± .005	.070 ± .003
-012	3/8 × 1/2 × 1/16	.364 ± .005	.070 ± .003
-013	7/16 × 9/16 × 1/16	.426 ± .005	.070 ± .003
-014	1/2 × 5/8 × 1/16	.489 ± .005	.070 ± .003
-015	9/16 × 11/16 × 1/16	.551 ± .007	.070 ± .003
-016	5/8 × 3/4 × 1/16	.614 ± .009	.070 ± .003
-017	11/16 × 13/16 × 1/16	.676 ± .009	.070 ± .003
-018	3/4 × 7/8 × 1/16	.739 ± .009	.070 ± .003
-019	13/16 × 15/16 × 1/16	.801 ± .009	.070 ± .003
-020	7/8 × 1 × 1/16	.864 ± .009	.070 ± .003
-021	15/16 × 1-1/16 × 1/16	.926 ± .009	.070 ± .003
-022	1 × — × 1/16	.989 ± .010	.070 ± .003
-023	1-1/16 × 1-3/16 × 1/16	1.051 ± .010	.070 ± .003
-024	1-1/8 × 1-1/4 × 1/16	1.114 ± .010	.070 ± .003
-025	1-3/16 × 1-5/16 × 1/16	1.176 ± .011	.070 ± .003
-026	1-1/4 × 1-3/8 × 1/16	1.239 ± .011	.070 ± .003
-027	1-5/16 × 1-7/16 × 1/16	1.301 ± .011	.070 ± .003
-028	1-3/8 × 1-1/2 × 1/16	1.364 ± .013	.070 ± .003
-029	1-1/2 × 1-5/8 × 1/16	1.489 ± .013	.070 ± .003
-030	1-5/8 × 1-3/4 × 1/16	1.614 ± .013	.070 ± .003
-031	1-3/4 × 1-7/8 × 1/16	1.739 ± .015	.070 ± .003
-032	1-7/8 × 2 × 1/16	1.864 ± .015	.070 ± .003
-033	2 × 2-1/8 × 1/16	1.989 ± .018	.070 ± .003
-034	2-1/8 × 2-1/4 × 1/16	2.114 ± .018	.070 ± .003
-035	2-1/4 × 2-3/8 × 1/16	2.239 ± .018	.070 ± .003
-036	2-3/8 × 2-1/2 × 1/16	2.364 ± .018	.070 ± .003
-037	2-1/2 × 2-5/8 × 1/16	2.489 ± .018	.070 ± .003
-038	2-5/8 × 2-3/4 × 1/16	2.614 ± .020	.070 ± .003
-039	2-3/4 × 2-7/8 × 1/16	2.739 ± .020	.070 ± .003
-040	2-7/8 × 3 × 1/16	2.864 ± .020	.070 ± .003
-041	3 × 3-1/8 × 1/16	2.989 ± .024	.070 ± .003
-042	3-1/4 × 3-3/8 × 1/16	3.239 ± .024	.070 ± .003
-043	3-1/2 × 3-5/8 × 1/16	3.489 ± .024	.070 ± .003
-044	3-3/4 × 3-7/8 × 1/16	3.739 ± .027	.070 ± .003
-045	4 × 4-1/8 × 1/16	3.989 ± .027	.070 ± .003
-046	4-1/4 × 4-3/8 × 1/16	4.239 ± .030	.070 ± .003
-047	4-1/2 × 4-5/8 × 1/16	4.489 ± .030	.070 ± .003
-048	4-3/4 × 4-7/8 × 1/16	4.739 ± .030	.070 ± .003
-049	5 × 5-1/8 × 1/16	4.989 ± .037	.070 ± .003
-050	5-1/4 × 5-3/8 × 1/16	5.239 ± .037	.070 ± .003

Inches. Nominal = the size’s name (fractions); ID and W = the actual ring, ± tolerance. A dash: our sources differ, or only one lists it — give us a call.

AS568 100 series — 3/32″ nominal cross-section
Dash	Nominal ID × OD × W	ID	W
-102	1/16 × 1/4 × 3/32	.049 ± —	.103 ± .003
-103	3/32 × 9/32 × 3/32	.081 ± .005	.103 ± .003
-104	1/8 × 5/16 × 3/32	.112 ± .005	.103 ± .003
-105	5/32 × 11/32 × 3/32	.143 ± .005	.103 ± .003
-106	3/16 × 3/8 × 3/32	.174 ± .005	.103 ± .003
-107	7/32 × 13/32 × 3/32	.206 ± .005	.103 ± .003
-108	1/4 × 7/16 × 3/32	.237 ± .005	.103 ± .003
-109	5/16 × 1/2 × 3/32	.299 ± .005	.103 ± .003
-110	3/8 × 9/16 × 3/32	.362 ± .005	.103 ± .003
-111	7/16 × 5/8 × 3/32	.424 ± .005	.103 ± .003
-112	1/2 × 11/16 × 3/32	.487 ± .005	.103 ± .003
-113	9/16 × 3/4 × 3/32	.549 ± .007	.103 ± .003
-114	5/8 × 13/16 × 3/32	.612 ± .009	.103 ± .003
-115	11/16 × 7/8 × 3/32	.674 ± .009	.103 ± .003
-116	3/4 × 15/16 × 3/32	.737 ± .009	.103 ± .003
-117	13/16 × 1 × 3/32	.799 ± .010	.103 ± .003
-118	7/8 × 1-1/16 × 3/32	.862 ± .010	.103 ± .003
-119	15/16 × 1-1/8 × 3/32	.924 ± .010	.103 ± .003
-120	1 × 1-3/16 × 3/32	.987 ± .010	.103 ± .003
-121	1-1/16 × 1-1/4 × 3/32	1.049 ± .010	.103 ± .003
-122	1-1/8 × 1-5/16 × 3/32	1.112 ± .010	.103 ± .003
-123	1-3/16 × 1-3/8 × 3/32	1.174 ± .012	.103 ± .003
-124	1-1/4 × 1-7/16 × 3/32	1.237 ± .012	.103 ± .003
-125	1-5/16 × 1-1/2 × 3/32	1.299 ± .012	.103 ± .003
-126	1-3/8 × 1-9/16 × 3/32	1.362 ± .012	.103 ± .003
-127	1-7/16 × 1-5/8 × 3/32	1.424 ± .012	.103 ± .003
-128	1-1/2 × 1-11/16 × 3/32	1.487 ± .012	.103 ± .003
-129	1-9/16 × 1-3/4 × 3/32	1.549 ± .015	.103 ± .003
-130	1-5/8 × 1-13/16 × 3/32	1.612 ± .015	.103 ± .003
-131	1-11/16 × 1-7/8 × 3/32	1.674 ± .015	.103 ± .003
-132	1-3/4 × 1-15/16 × 3/32	1.737 ± .015	.103 ± .003
-133	1-13/16 × 2 × 3/32	1.799 ± .015	.103 ± .003
-134	1-7/8 × 2-1/16 × 3/32	1.862 ± .015	.103 ± .003
-135	1-15/16 × 2-1/8 × 3/32	1.925 ± .017	.103 ± .003
-136	2 × 2-3/16 × 3/32	1.987 ± .017	.103 ± .003
-137	2-1/16 × 2-1/4 × 3/32	2.050 ± .017	.103 ± .003
-138	2-1/8 × 2-5/16 × 3/32	2.112 ± .017	.103 ± .003
-139	2-3/16 × 2-3/8 × 3/32	2.175 ± .017	.103 ± .003
-140	2-1/4 × 2-7/16 × 3/32	2.237 ± .017	.103 ± .003
-141	2-5/16 × 2-1/2 × 3/32	2.300 ± .020	.103 ± .003
-142	2-3/8 × 2-9/16 × 3/32	2.362 ± .020	.103 ± .003
-143	2-7/16 × 2-5/8 × 3/32	2.425 ± .020	.103 ± .003
-144	2-1/2 × 2-11/16 × 3/32	2.487 ± .020	.103 ± .003
-145	2-9/16 × 2-3/4 × 3/32	2.550 ± .020	.103 ± .003
-146	2-5/8 × 2-13/16 × 3/32	2.612 ± .020	.103 ± .003
-147	2-11/16 × 2-7/8 × 3/32	2.675 ± .022	.103 ± .003
-148	2-3/4 × 2-15/16 × 3/32	2.737 ± .022	.103 ± .003
-149	2-13/16 × 3 × 3/32	2.800 ± .022	.103 ± .003
-150	2-7/8 × 3-1/16 × 3/32	2.862 ± .022	.103 ± .003
-151	3 × 3-3/16 × 3/32	2.987 ± .024	.103 ± .003
-152	3-1/4 × 3-7/16 × 3/32	3.237 ± .024	.103 ± .003
-153	3-1/2 × 3-11/16 × 3/32	3.487 ± .024	.103 ± .003
-154	3-3/4 × 3-15/16 × 3/32	3.737 ± .028	.103 ± .003
-155	4 × 4-3/16 × 3/32	3.987 ± .028	.103 ± .003
-156	4-1/4 × 4-7/16 × 3/32	4.237 ± .030	.103 ± .003
-157	4-1/2 × 4-11/16 × 3/32	4.487 ± .030	.103 ± .003
-158	4-3/4 × 4-15/16 × 3/32	4.737 ± .030	.103 ± .003
-159	5 × 5-3/16 × 3/32	4.987 ± .035	.103 ± .003
-160	5-1/4 × 5-7/16 × 3/32	5.237 ± .035	.103 ± .003
-161	5-1/2 × 5-11/16 × 3/32	5.487 ± .035	.103 ± .003
-162	5-3/4 × 5-15/16 × 3/32	5.737 ± .035	.103 ± .003
-163	6 × 6-3/16 × 3/32	5.987 ± .035	.103 ± .003
-164	6-1/4 × 6-7/16 × 3/32	6.237 ± .040	.103 ± .003
-165	6-1/2 × 6-11/16 × 3/32	6.487 ± .040	.103 ± .003
-166	6-3/4 × 6-15/16 × 3/32	6.737 ± .040	.103 ± .003
-167	7 × 7-3/16 × 3/32	6.987 ± .040	.103 ± .003
-168	7-1/4 × 7-7/16 × 3/32	7.237 ± .045	.103 ± .003
-169	7-1/2 × 7-11/16 × 3/32	7.487 ± .045	.103 ± .003
-170	7-3/4 × 7-15/16 × 3/32	7.737 ± .045	.103 ± .003
-171	8 × 8-3/16 × 3/32	7.987 ± .045	.103 ± .003
-172	8-1/4 × 8-7/16 × 3/32	8.237 ± .050	.103 ± .003
-173	8-1/2 × 8-11/16 × 3/32	8.487 ± .050	.103 ± .003
-174	8-3/4 × 8-15/16 × 3/32	8.737 ± .050	.103 ± .003
-175	9 × 9-3/16 × 3/32	8.987 ± .050	.103 ± .003
-176	9-1/4 × 9-7/16 × 3/32	9.237 ± .055	.103 ± .003
-177	9-1/2 × 9-11/16 × 3/32	9.487 ± .055	.103 ± .003
-178	9-3/4 × 9-15/16 × 3/32	9.737 ± .055	.103 ± .003

Inches. Nominal = the size’s name (fractions); ID and W = the actual ring, ± tolerance. A dash: our sources differ, or only one lists it — give us a call.

AS568 200 series — 1/8″ nominal cross-section
Dash	Nominal ID × OD × W	ID	W
-201	3/16 × 7/16 × 1/8	.171 ± —	.139 ± .004
-202	1/4 × 1/2 × 1/8	.234 ± .005	.139 ± .004
-203	5/16 × 9/16 × 1/8	.296 ± .005	.139 ± .004
-204	3/8 × 5/8 × 1/8	.359 ± .005	.139 ± .004
-205	7/16 × 11/16 × 1/8	.421 ± .005	.139 ± .004
-206	1/2 × 3/4 × 1/8	.484 ± .005	.139 ± .004
-207	9/16 × 13/16 × 1/8	.546 ± .007	.139 ± .004
-208	5/8 × 7/8 × 1/8	.609 ± .009	.139 ± .004
-209	11/16 × 15/16 × 1/8	.671 ± —	.139 ± .004
-210	3/4 × 1 × 1/8	.734 ± .010	.139 ± .004
-211	13/16 × 1-1/16 × 1/8	.796 ± .010	.139 ± .004
-212	7/8 × 1-1/8 × 1/8	.859 ± .010	.139 ± .004
-213	15/16 × 1-3/16 × 1/8	.921 ± .010	.139 ± .004
-214	1 × 1-1/4 × 1/8	.984 ± .010	.139 ± .004
-215	1-1/16 × 1-5/16 × 1/8	1.046 ± .010	.139 ± .004
-216	1-1/8 × 1-3/8 × 1/8	1.109 ± .012	.139 ± .004
-217	1-3/16 × 1-7/16 × 1/8	1.171 ± .012	.139 ± .004
-218	1-1/4 × 1-1/2 × 1/8	1.234 ± .012	.139 ± .004
-219	1-5/16 × 1-9/16 × 1/8	1.296 ± .012	.139 ± .004
-220	1-3/8 × 1-5/8 × 1/8	1.359 ± .012	.139 ± .004
-221	1-7/16 × 1-11/16 × 1/8	1.421 ± .012	.139 ± .004
-222	1-1/2 × 1-3/4 × 1/8	1.484 ± .015	.139 ± .004
-223	1-5/8 × 1-7/8 × 1/8	1.609 ± .015	.139 ± .004
-224	1-3/4 × 2 × 1/8	1.734 ± .015	.139 ± .004
-225	1-7/8 × 2-1/8 × 1/8	1.859 ± .018	.139 ± .004
-226	2 × 2-1/4 × 1/8	1.984 ± .018	.139 ± .004
-227	— × 2-3/8 × 1/8	2.109 ± .018	.139 ± .004
-228	2-1/4 × 2-1/2 × 1/8	2.234 ± .020	.139 ± .004
-229	2-3/8 × 2-5/8 × 1/8	2.359 ± .020	.139 ± .004
-230	2-1/2 × 2-3/4 × 1/8	2.484 ± .020	.139 ± .004
-231	2-5/8 × 2-7/8 × 1/8	2.609 ± .020	.139 ± .004
-232	2-3/4 × 3 × 1/8	2.734 ± .024	.139 ± .004
-233	2-7/8 × 3-1/8 × 1/8	2.859 ± .024	.139 ± .004
-234	3 × 3-1/4 × 1/8	2.984 ± .024	.139 ± .004
-235	3-1/8 × 3-3/8 × 1/8	3.109 ± .024	.139 ± .004
-236	3-1/4 × 3-1/2 × 1/8	3.234 ± .024	.139 ± .004
-237	3-3/8 × 3-5/8 × 1/8	3.359 ± .024	.139 ± .004
-238	3-1/2 × 3-3/4 × 1/8	3.484 ± .024	.139 ± .004
-239	3-5/8 × 3-7/8 × 1/8	3.609 ± .028	.139 ± .004
-240	3-3/4 × 4 × 1/8	3.734 ± .028	.139 ± .004
-241	3-7/8 × 4-1/8 × 1/8	3.859 ± .028	.139 ± .004
-242	4 × 4-1/4 × 1/8	3.984 ± .028	.139 ± .004
-243	4-1/8 × 4-3/8 × 1/8	4.109 ± .028	.139 ± .004
-244	4-1/4 × 4-1/2 × 1/8	4.234 ± .030	.139 ± .004
-245	4-3/8 × 4-5/8 × 1/8	4.359 ± .030	.139 ± .004
-246	4-1/2 × 4-3/4 × 1/8	4.484 ± .030	.139 ± .004
-247	4-5/8 × 4-7/8 × 1/8	4.609 ± .030	.139 ± .004
-248	4-3/4 × 5 × 1/8	4.734 ± .030	.139 ± .004
-249	4-7/8 × 5-1/8 × 1/8	4.859 ± .035	.139 ± .004
-250	5 × 5-1/4 × 1/8	4.984 ± .035	.139 ± .004
-251	5-1/8 × 5-3/8 × 1/8	5.109 ± .035	.139 ± .004
-252	5-1/4 × 5-1/2 × 1/8	5.234 ± .035	.139 ± .004
-253	5-3/8 × 5-5/8 × 1/8	5.359 ± .035	.139 ± .004
-254	5-1/2 × 5-3/4 × 1/8	5.484 ± .035	.139 ± .004
-255	5-5/8 × 5-7/8 × 1/8	5.609 ± .035	.139 ± .004
-256	5-3/4 × 6 × 1/8	5.734 ± .035	.139 ± .004
-257	5-7/8 × 6-1/8 × 1/8	5.859 ± .035	.139 ± .004
-258	6 × 6-1/4 × 1/8	5.984 ± .035	.139 ± .004
-259	6-1/4 × 6-1/2 × 1/8	6.234 ± .040	.139 ± .004
-260	6-1/2 × 6-3/4 × 1/8	6.484 ± .040	.139 ± .004
-261	6-3/4 × 7 × 1/8	6.734 ± .040	.139 ± .004
-262	7 × 7-1/4 × 1/8	6.984 ± .040	.139 ± .004
-263	7-1/4 × 7-1/2 × 1/8	7.234 ± .045	.139 ± .004
-264	7-1/2 × — × 1/8	7.484 ± .045	.139 ± .004
-265	7-3/4 × 8 × 1/8	7.734 ± .045	.139 ± .004
-266	8 × 8-1/4 × 1/8	7.984 ± .045	.139 ± .004
-267	8-1/4 × 8-1/2 × 1/8	8.234 ± .050	.139 ± .004
-268	8-1/2 × 8-3/4 × 1/8	8.484 ± .050	.139 ± .004
-269	8-3/4 × 9 × 1/8	8.734 ± .050	.139 ± .004
-270	9 × 9-1/4 × 1/8	8.984 ± .050	.139 ± .004
-271	9-1/4 × 9-1/2 × 1/8	9.234 ± .055	.139 ± .004
-272	9-1/2 × 9-3/4 × 1/8	9.484 ± .055	.139 ± .004
-273	9-3/4 × 10 × 1/8	9.734 ± .055	.139 ± .004
-274	10 × 10-1/4 × 1/8	9.984 ± .055	.139 ± .004
-275	10-1/2 × 10-3/4 × 1/8	10.484 ± .055	.139 ± .004
-276	11 × 11-1/4 × 1/8	10.984 ± .065	.139 ± .004
-277	11-1/2 × 11-3/4 × 1/8	11.484 ± .065	.139 ± .004
-278	12 × 12-1/4 × 1/8	11.984 ± .065	.139 ± .004
-279	13 × 13-1/4 × 1/8	12.984 ± .065	.139 ± .004
-280	14 × 14-1/4 × 1/8	13.984 ± .065	.139 ± .004
-281	15 × 15-1/4 × 1/8	14.984 ± .065	.139 ± .004
-282	16 × 16-1/4 × 1/8	15.955 ± .075	.139 ± .004
-283	17 × 17-1/4 × 1/8	16.955 ± .080	.139 ± .004
-284	18 × 18-1/4 × 1/8	17.955 ± .085	.139 ± .004

Inches. Nominal = the size’s name (fractions); ID and W = the actual ring, ± tolerance. A dash: our sources differ, or only one lists it — give us a call.

AS568 300 series — 3/16″ nominal cross-section
Dash	Nominal ID × OD × W	ID	W
-309	7/16 × 13/16 × 3/16	.412 ± .005	.210 ± .005
-310	1/2 × 7/8 × 3/16	.475 ± .005	.210 ± .005
-311	9/16 × 15/16 × 3/16	.537 ± .007	.210 ± .005
-312	5/8 × 1 × 3/16	.600 ± .009	.210 ± .005
-313	11/16 × 1-1/16 × 3/16	.662 ± .009	.210 ± .005
-314	3/4 × 1-1/8 × 3/16	.725 ± .010	.210 ± .005
-315	13/16 × 1-3/16 × 3/16	.787 ± .010	.210 ± .005
-316	7/8 × 1-1/4 × 3/16	.850 ± .010	.210 ± .005
-317	15/16 × 1-5/16 × 3/16	.912 ± .010	.210 ± .005
-318	1 × 1-3/8 × 3/16	.975 ± .010	.210 ± .005
-319	1-1/16 × 1-7/16 × 3/16	1.037 ± .010	.210 ± .005
-320	1-1/8 × 1-1/2 × 3/16	1.100 ± .012	.210 ± .005
-321	1-3/16 × 1-9/16 × 3/16	1.162 ± .012	.210 ± .005
-322	1-1/4 × 1-5/8 × 3/16	1.225 ± .012	.210 ± .005
-323	1-5/16 × 1-11/16 × 3/16	1.287 ± .012	.210 ± .005
-324	1-3/8 × 1-3/4 × 3/16	1.350 ± .012	.210 ± .005
-325	1-1/2 × 1-7/8 × 3/16	1.475 ± .015	.210 ± .005
-326	1-5/8 × 2 × 3/16	1.600 ± .015	.210 ± .005
-327	1-3/4 × 2-1/8 × 3/16	1.725 ± .015	.210 ± .005
-328	1-7/8 × 2-1/4 × 3/16	1.850 ± .015	.210 ± .005
-329	2 × 2-3/8 × 3/16	1.975 ± .018	.210 ± .005
-330	2-1/8 × 2-1/2 × 3/16	2.100 ± .018	.210 ± .005
-331	2-1/4 × 2-5/8 × 3/16	2.225 ± .018	.210 ± .005
-332	2-3/8 × 2-3/4 × 3/16	2.350 ± .018	.210 ± .005
-333	2-1/2 × 2-7/8 × 3/16	2.475 ± .020	.210 ± .005
-334	2-5/8 × 3 × 3/16	2.600 ± .020	.210 ± .005
-335	2-3/4 × 3-1/8 × 3/16	2.725 ± .020	.210 ± .005
-336	2-7/8 × 3-1/4 × 3/16	2.850 ± .020	.210 ± .005
-337	3 × 3-3/8 × 3/16	2.975 ± .024	.210 ± .005
-338	3-1/8 × 3-1/2 × 3/16	3.100 ± .024	.210 ± .005
-339	3-1/4 × 3-5/8 × 3/16	3.225 ± .024	.210 ± .005
-340	3-3/8 × 3-3/4 × 3/16	3.350 ± .024	.210 ± .005
-341	3-1/2 × 3-7/8 × 3/16	3.475 ± .024	.210 ± .005
-342	3-5/8 × 4 × 3/16	3.600 ± .028	.210 ± .005
-343	3-3/4 × 4-1/8 × 3/16	3.725 ± .028	.210 ± .005
-344	3-7/8 × 4-1/4 × 3/16	3.850 ± .028	.210 ± .005
-345	4 × 4-3/8 × 3/16	3.975 ± .028	.210 ± .005
-346	4-1/8 × 4-1/2 × 3/16	4.100 ± .028	.210 ± .005
-347	4-1/4 × 4-5/8 × 3/16	4.225 ± .030	.210 ± .005
-348	4-3/8 × 4-3/4 × 3/16	4.350 ± .030	.210 ± .005
-349	4-1/2 × 4-7/8 × 3/16	4.475 ± .030	.210 ± .005
-350	4-5/8 × 5 × 3/16	4.600 ± .030	.210 ± .005
-351	4-3/4 × 5-1/8 × 3/16	4.725 ± .030	.210 ± .005
-352	4-7/8 × 5-1/4 × 3/16	4.850 ± .030	.210 ± .005
-353	5 × 5-3/8 × 3/16	4.975 ± .037	.210 ± .005
-354	5-1/8 × 5-1/2 × 3/16	5.100 ± .037	.210 ± .005
-355	5-1/4 × 5-5/8 × 3/16	5.225 ± .037	.210 ± .005
-356	5-3/8 × 5-3/4 × 3/16	5.350 ± .037	.210 ± .005
-357	5-1/2 × 5-7/8 × 3/16	5.475 ± .037	.210 ± .005
-358	5-5/8 × 6 × 3/16	5.600 ± .037	.210 ± .005
-359	5-3/4 × 6-1/8 × 3/16	5.725 ± .037	.210 ± .005
-360	5-7/8 × 6-1/4 × 3/16	5.850 ± .037	.210 ± .005
-361	6 × 6-3/8 × 3/16	5.975 ± .037	.210 ± .005
-362	6-1/4 × 6-5/8 × 3/16	6.225 ± .040	.210 ± .005
-363	6-1/2 × 6-7/8 × 3/16	6.475 ± .040	.210 ± .005
-364	6-3/4 × 7-1/8 × 3/16	6.725 ± .040	.210 ± .005
-365	7 × 7-3/8 × 3/16	6.975 ± .040	.210 ± .005
-366	7-1/4 × 7-5/8 × 3/16	7.225 ± .045	.210 ± .005
-367	7-1/2 × 7-7/8 × 3/16	7.475 ± .045	.210 ± .005
-368	7-3/4 × 8-1/8 × 3/16	7.725 ± .045	.210 ± .005
-369	8 × 8-3/8 × 3/16	7.975 ± .045	.210 ± .005
-370	8-1/4 × 8-5/8 × 3/16	8.225 ± .050	.210 ± .005
-371	8-1/2 × 8-7/8 × 3/16	8.475 ± .050	.210 ± .005
-372	8-3/4 × 9-1/8 × 3/16	8.725 ± .050	.210 ± .005
-373	9 × 9-3/8 × 3/16	8.975 ± .050	.210 ± .005
-374	9-1/4 × 9-5/8 × 3/16	9.225 ± .055	.210 ± .005
-375	9-1/2 × 9-7/8 × 3/16	9.475 ± .055	.210 ± .005
-376	9-3/4 × 10-1/8 × 3/16	9.725 ± .055	.210 ± .005
-377	10 × 10-3/8 × 3/16	9.975 ± .055	.210 ± .005
-378	10-1/2 × 10-7/8 × 3/16	10.475 ± .060	.210 ± .005
-379	11 × 11-3/8 × 3/16	10.975 ± .060	.210 ± .005
-380	11-1/2 × 11-7/8 × 3/16	11.475 ± .065	.210 ± .005
-381	12 × 12-3/8 × 3/16	11.975 ± .065	.210 ± .005
-382	13 × 13-3/8 × 3/16	12.975 ± .065	.210 ± .005
-383	14 × 14-3/8 × 3/16	13.975 ± .070	.210 ± .005
-384	15 × 15-3/8 × 3/16	14.975 ± .070	.210 ± .005
-385	16 × 16-3/8 × 3/16	15.955 ± .075	.210 ± .005
-386	17 × 17-3/8 × 3/16	16.955 ± .080	.210 ± .005
-387	18 × 18-3/8 × 3/16	17.955 ± .085	.210 ± .005
-388	19 × 19-3/8 × 3/16	18.955 ± .090	.210 ± .005
-389	20 × 20-3/8 × 3/16	19.955 ± .095	.210 ± .005
-390	21 × 21-3/8 × 3/16	20.955 ± .095	.210 ± .005
-391	22 × 22-3/8 × 3/16	—	.210 ± .005
-392	23 × 23-3/8 × 3/16	22.940 ± .105	.210 ± .005
-393	24 × 24-3/8 × 3/16	23.940 ± .110	.210 ± .005
-394	25 × 25-3/8 × 3/16	24.940 ± .115	.210 ± .005
-395	26 × 26-3/8 × 3/16	25.940 ± .120	.210 ± .005

Inches. Nominal = the size’s name (fractions); ID and W = the actual ring, ± tolerance. A dash: our sources differ, or only one lists it — give us a call.

AS568 400 series — 1/4″ nominal cross-section
Dash	Nominal ID × OD × W	ID	W
-425	4-1/2 × 5 × 1/4	4.475 ± .033	.275 ± .006
-426	4-5/8 × 5-1/8 × 1/4	4.600 ± .033	.275 ± .006
-427	4-3/4 × 5-1/4 × 1/4	4.725 ± .033	.275 ± .006
-428	4-7/8 × 5-3/8 × 1/4	4.850 ± .033	.275 ± .006
-429	5 × 5-1/2 × 1/4	4.975 ± .037	.275 ± .006
-430	5-1/8 × 5-5/8 × 1/4	5.100 ± .037	.275 ± .006
-431	5-1/4 × 5-3/4 × 1/4	5.225 ± .037	.275 ± .006
-432	5-3/8 × 5-7/8 × 1/4	5.350 ± .037	.275 ± .006
-433	5-1/2 × 6 × 1/4	5.475 ± .037	.275 ± .006
-434	5-5/8 × 6-1/8 × 1/4	5.600 ± .037	.275 ± .006
-435	5-3/4 × 6-1/4 × 1/4	5.725 ± .037	.275 ± .006
-436	5-7/8 × 6-3/8 × 1/4	5.850 ± .037	.275 ± .006
-437	6 × 6-1/2 × 1/4	5.975 ± .037	.275 ± .006
-438	6-1/4 × 6-3/4 × 1/4	6.225 ± .040	.275 ± .006
-439	6-1/2 × 7 × 1/4	6.475 ± .040	.275 ± .006
-440	6-3/4 × 7-1/4 × 1/4	6.725 ± .040	.275 ± .006
-441	7 × 7-1/2 × 1/4	6.975 ± .040	.275 ± .006
-442	7-1/4 × 7-3/4 × 1/4	7.225 ± .045	.275 ± .006
-443	7-1/2 × 8 × 1/4	7.475 ± .045	.275 ± .006
-444	7-3/4 × 8-1/4 × 1/4	7.725 ± .045	.275 ± .006
-445	8 × 8-1/2 × 1/4	7.975 ± .045	.275 ± .006
-446	8-1/2 × 9 × 1/4	8.475 ± .055	.275 ± .006
-447	9 × 9-1/2 × 1/4	8.975 ± .055	.275 ± .006
-448	9-1/2 × 10 × 1/4	9.475 ± .055	.275 ± .006
-449	10 × 10-1/2 × 1/4	9.975 ± .055	.275 ± .006
-450	10-1/2 × 11 × 1/4	10.475 ± .060	.275 ± .006
-451	11 × 11-1/2 × 1/4	10.975 ± .060	.275 ± .006
-452	— × — × —	11.475 ± .060	.275 ± .006
-453	12 × 12-1/2 × 1/4	11.975 ± .060	.275 ± .006
-454	12-1/2 × 13 × 1/4	12.475 ± .060	.275 ± .006
-455	13 × 13-1/2 × 1/4	12.975 ± .060	.275 ± .006
-456	13-1/2 × 14 × 1/4	13.475 ± .070	.275 ± .006
-457	14 × 14-1/2 × 1/4	13.975 ± .070	.275 ± .006
-458	14-1/2 × 15 × 1/4	14.475 ± .070	.275 ± .006
-459	15 × 15-1/2 × 1/4	14.975 ± .070	.275 ± .006
-460	15-1/2 × 16 × 1/4	15.475 ± .070	.275 ± .006
-461	16 × 16-1/2 × 1/4	15.955 ± .075	.275 ± .006
-462	16-1/2 × 17 × 1/4	16.455 ± .075	.275 ± .006
-463	17 × 17-1/2 × 1/4	16.955 ± .080	.275 ± .006
-464	17-1/2 × 18 × 1/4	17.455 ± .085	.275 ± .006
-465	18 × 18-1/2 × 1/4	17.955 ± .085	.275 ± .006
-466	18-1/2 × 19 × 1/4	18.455 ± .085	.275 ± .006
-467	19 × 19-1/2 × 1/4	18.955 ± .090	.275 ± .006
-468	19-1/2 × 20 × 1/4	19.455 ± .090	.275 ± .006
-469	20 × 20-1/2 × 1/4	19.955 ± .095	.275 ± .006
-470	21 × 21-1/2 × 1/4	20.955 ± .095	.275 ± .006
-471	22 × 22-1/2 × 1/4	21.955 ± .100	.275 ± .006
-472	23 × 23-1/2 × 1/4	22.940 ± .105	.275 ± .006
-473	24 × 24-1/2 × 1/4	23.940 ± .110	.275 ± .006
-474	25 × 25-1/2 × 1/4	24.940 ± .115	.275 ± .006
-475	26 × 26-1/2 × 1/4	25.940 ± .120	.275 ± .006

Inches. Nominal = the size’s name (fractions); ID and W = the actual ring, ± tolerance. A dash: our sources differ, or only one lists it — give us a call.

AS568 900 series — tube fitting boss gaskets
Dash	Tube OD	ID	W
-901	3/32″	.185 ± .005	.056 ± .003
-902	1/8″	.239 ± .005	.064 ± .003
-903	3/16″	.301 ± .005	.064 ± .003
-904	1/4″	.351 ± .005	.072 ± .003
-905	5/16″	.414 ± .005	.072 ± .003
-906	3/8″	.468 ± .005	.078 ± .003
-907	7/16″	.530 ± .007	.082 ± .003
-908	1/2″	.644 ± .009	.087 ± .003
-909	9/16″	.706 ± .009	.097 ± .003
-910	5/8″	.755 ± .009	.097 ± .003
-911	11/16″	.863 ± .009	.116 ± .004
-912	3/4″	.924 ± .009	.116 ± .004
-913	13/16″	.986 ± .010	.116 ± .004
-914	7/8″	1.047 ± .010	.116 ± .004
-916	1″	1.171 ± .010	.116 ± .004
-918	1-1/8″	1.355 ± .012	.116 ± .004
-920	1-1/4″	1.475 ± .014	.118 ± .004
-924	1-1/2″	1.720 ± .014	.118 ± .004
-928	1-3/4″	2.090 ± .018	.118 ± .004
-932	2″	2.337 ± .018	.118 ± .004

Inches. For straight thread O-ring boss ports and tube fittings: the tube OD the size goes with, then the actual ring, ± tolerance.

Metric sizes of AS568 O-rings
Dash	ID (mm)	W (mm)
-001	0.74 ± 0.10	1.02 ± 0.08
-002	1.07 ± 0.10	1.27 ± 0.08
-003	1.42 ± 0.10	1.52 ± 0.08
-004	1.78 ± 0.13	1.78 ± 0.08
-005	2.57 ± 0.13	1.78 ± 0.08
-006	2.90 ± 0.13	1.78 ± 0.08
-007	—	1.78 ± 0.08
-008	4.47 ± 0.13	1.78 ± 0.08
-009	5.28 ± 0.13	1.78 ± 0.08
-010	6.07 ± 0.13	1.78 ± 0.08
-011	—	1.78 ± 0.08
-012	9.25 ± 0.13	1.78 ± 0.08
-013	10.82 ± 0.13	1.78 ± 0.08
-014	12.42 ± 0.13	1.78 ± 0.08
-015	14.00 ± 0.18	1.78 ± 0.08
-016	15.60 ± 0.23	1.78 ± 0.08
-017	—	1.78 ± 0.08
-018	18.77 ± 0.23	1.78 ± 0.08
-019	20.35 ± 0.23	1.78 ± 0.08
-020	21.95 ± 0.23	1.78 ± 0.08
-021	23.52 ± 0.23	1.78 ± 0.08
-022	25.12 ± 0.25	1.78 ± 0.08
-023	26.70 ± 0.25	1.78 ± 0.08
-024	28.30 ± 0.25	1.78 ± 0.08
-025	29.87 ± 0.28	1.78 ± 0.08
-026	31.47 ± 0.28	1.78 ± 0.08
-027	33.05 ± 0.28	1.78 ± 0.08
-028	34.65 ± 0.33	1.78 ± 0.08
-029	37.82 ± 0.33	1.78 ± 0.08
-030	41.00 ± 0.33	1.78 ± 0.08
-031	44.17 ± 0.38	1.78 ± 0.08
-032	—	1.78 ± 0.08
-033	50.52 ± 0.46	1.78 ± 0.08
-034	—	1.78 ± 0.08
-035	56.87 ± 0.46	1.78 ± 0.08
-036	—	1.78 ± 0.08
-037	63.22 ± 0.46	1.78 ± 0.08
-038	66.40 ± 0.51	1.78 ± 0.08
-039	69.57 ± 0.51	1.78 ± 0.08
-040	—	1.78 ± 0.08
-041	75.92 ± 0.61	1.78 ± 0.08
-042	82.27 ± 0.61	1.78 ± 0.08
-043	88.62 ± 0.61	1.78 ± 0.08
-044	94.97 ± 0.69	1.78 ± 0.08
-045	101.32 ± 0.69	1.78 ± 0.08
-046	107.67 ± 0.76	1.78 ± 0.08
-047	114.02 ± 0.76	1.78 ± 0.08
-048	120.37 ± 0.76	1.78 ± 0.08
-049	126.72 ± 0.94	1.78 ± 0.08
-050	133.07 ± 0.94	1.78 ± 0.08
-102	1.24 ± —	2.62 ± 0.08
-103	2.06 ± 0.13	2.62 ± 0.08
-104	2.84 ± 0.13	2.62 ± 0.08
-105	3.63 ± 0.13	2.62 ± 0.08
-106	—	2.62 ± 0.08
-107	5.23 ± 0.13	2.62 ± 0.08
-108	6.02 ± 0.13	2.62 ± 0.08
-109	7.59 ± 0.13	2.62 ± 0.08
-110	9.19 ± 0.13	2.62 ± 0.08
-111	10.77 ± 0.13	2.62 ± 0.08
-112	12.37 ± 0.13	2.62 ± 0.08
-113	13.94 ± 0.18	2.62 ± 0.08
-114	15.54 ± 0.23	2.62 ± 0.08
-115	17.12 ± 0.23	2.62 ± 0.08
-116	18.72 ± 0.23	2.62 ± 0.08
-117	20.29 ± 0.25	2.62 ± 0.08
-118	21.89 ± 0.25	2.62 ± 0.08
-119	23.47 ± 0.25	2.62 ± 0.08
-120	25.07 ± 0.25	2.62 ± 0.08
-121	26.64 ± 0.25	2.62 ± 0.08
-122	28.24 ± 0.25	2.62 ± 0.08
-123	29.82 ± 0.30	2.62 ± 0.08
-124	31.42 ± 0.30	2.62 ± 0.08
-125	32.99 ± 0.30	2.62 ± 0.08
-126	34.59 ± 0.30	2.62 ± 0.08
-127	36.17 ± 0.30	2.62 ± 0.08
-128	37.77 ± 0.30	2.62 ± 0.08
-129	39.34 ± 0.38	2.62 ± 0.08
-130	40.94 ± 0.38	2.62 ± 0.08
-131	42.52 ± 0.38	2.62 ± 0.08
-132	44.12 ± 0.38	2.62 ± 0.08
-133	45.69 ± 0.38	2.62 ± 0.08
-134	47.29 ± —	2.62 ± 0.08
-135	48.90 ± 0.43	2.62 ± 0.08
-136	50.47 ± 0.43	2.62 ± 0.08
-137	52.07 ± 0.43	2.62 ± 0.08
-138	53.64 ± 0.43	2.62 ± 0.08
-139	55.25 ± 0.43	2.62 ± 0.08
-140	56.82 ± 0.43	2.62 ± 0.08
-141	58.42 ± 0.51	2.62 ± 0.08
-142	59.99 ± 0.51	2.62 ± 0.08
-143	61.60 ± 0.51	2.62 ± 0.08
-144	63.17 ± 0.51	2.62 ± 0.08
-145	64.77 ± 0.51	2.62 ± 0.08
-146	66.34 ± 0.51	2.62 ± 0.08
-147	67.95 ± 0.56	2.62 ± 0.08
-148	69.52 ± 0.56	2.62 ± 0.08
-149	71.12 ± 0.56	2.62 ± 0.08
-150	72.69 ± 0.56	2.62 ± 0.08
-151	75.87 ± 0.61	2.62 ± 0.08
-152	82.22 ± 0.61	2.62 ± 0.08
-153	88.57 ± 0.61	2.62 ± 0.08
-154	94.92 ± 0.71	2.62 ± 0.08
-155	101.27 ± 0.71	2.62 ± 0.08
-156	107.62 ± 0.76	2.62 ± 0.08
-157	113.97 ± 0.76	2.62 ± 0.08
-158	120.32 ± 0.76	2.62 ± 0.08
-159	126.67 ± 0.89	2.62 ± 0.08
-160	133.02 ± 0.89	2.62 ± 0.08
-161	139.37 ± 0.89	2.62 ± 0.08
-162	145.72 ± 0.89	2.62 ± 0.08
-163	152.07 ± 0.89	2.62 ± 0.08
-164	158.42 ± 1.02	2.62 ± 0.08
-165	164.77 ± 1.02	2.62 ± 0.08
-166	171.12 ± 1.02	2.62 ± 0.08
-167	177.47 ± 1.02	2.62 ± 0.08
-168	183.82 ± 1.14	2.62 ± 0.08
-169	190.17 ± 1.14	2.62 ± 0.08
-170	196.52 ± 1.14	2.62 ± 0.08
-171	202.87 ± 1.14	2.62 ± 0.08
-172	209.22 ± 1.27	2.62 ± 0.08
-173	215.57 ± 1.27	2.62 ± 0.08
-174	221.92 ± 1.27	2.62 ± 0.08
-175	228.27 ± 1.27	2.62 ± 0.08
-176	234.62 ± 1.40	2.62 ± 0.08
-177	240.97 ± 1.40	2.62 ± 0.08
-178	247.32 ± 1.40	2.62 ± 0.08
-201	4.34 ± 0.13	3.53 ± 0.10
-202	5.94 ± 0.13	3.53 ± 0.10
-203	7.52 ± 0.13	3.53 ± 0.10
-204	9.12 ± 0.13	3.53 ± 0.10
-205	10.69 ± 0.13	3.53 ± 0.10
-206	12.29 ± 0.13	3.53 ± 0.10
-207	13.87 ± 0.18	3.53 ± 0.10
-208	15.47 ± 0.23	3.53 ± 0.10
-209	17.04 ± 0.23	3.53 ± 0.10
-210	18.64 ± 0.25	3.53 ± 0.10
-211	20.22 ± 0.25	3.53 ± 0.10
-212	21.82 ± 0.25	3.53 ± 0.10
-213	23.39 ± 0.25	3.53 ± 0.10
-214	24.99 ± 0.25	3.53 ± 0.10
-215	26.57 ± 0.25	3.53 ± 0.10
-216	28.17 ± 0.30	3.53 ± 0.10
-217	29.74 ± 0.30	3.53 ± 0.10
-218	31.34 ± 0.30	3.53 ± 0.10
-219	32.92 ± 0.30	3.53 ± 0.10
-220	34.52 ± 0.30	3.53 ± 0.10
-221	36.09 ± 0.30	3.53 ± 0.10
-222	37.69 ± 0.38	3.53 ± 0.10
-223	40.87 ± 0.38	3.53 ± 0.10
-224	44.04 ± 0.38	3.53 ± 0.10
-225	47.22 ± 0.46	3.53 ± 0.10
-226	50.39 ± 0.46	3.53 ± 0.10
-227	53.57 ± 0.46	3.53 ± 0.10
-228	56.74 ± 0.51	3.53 ± 0.10
-229	59.92 ± 0.51	3.53 ± 0.10
-230	63.09 ± 0.51	3.53 ± 0.10
-231	66.27 ± 0.51	3.53 ± 0.10
-232	69.44 ± 0.61	3.53 ± 0.10
-233	72.62 ± 0.61	3.53 ± 0.10
-234	75.79 ± 0.61	3.53 ± 0.10
-235	78.97 ± 0.61	3.53 ± 0.10
-236	82.14 ± 0.61	3.53 ± 0.10
-237	85.32 ± 0.61	3.53 ± 0.10
-238	88.49 ± 0.61	3.53 ± 0.10
-239	91.67 ± 0.71	3.53 ± 0.10
-240	94.84 ± 0.71	3.53 ± 0.10
-241	98.02 ± 0.71	3.53 ± 0.10
-242	101.19 ± 0.71	3.53 ± 0.10
-243	104.37 ± 0.71	3.53 ± 0.10
-244	107.54 ± 0.76	3.53 ± 0.10
-245	110.72 ± 0.76	3.53 ± 0.10
-246	113.89 ± 0.76	3.53 ± 0.10
-247	117.07 ± 0.76	3.53 ± 0.10
-248	120.24 ± 0.76	3.53 ± 0.10
-249	123.42 ± 0.89	3.53 ± 0.10
-250	126.59 ± 0.89	3.53 ± 0.10
-251	129.77 ± 0.89	3.53 ± 0.10
-252	132.94 ± 0.89	3.53 ± 0.10
-253	136.12 ± 0.89	3.53 ± 0.10
-254	139.29 ± 0.89	3.53 ± 0.10
-255	142.47 ± 0.89	3.53 ± 0.10
-256	145.64 ± 0.89	3.53 ± 0.10
-257	148.82 ± 0.89	3.53 ± 0.10
-258	151.99 ± 0.89	3.53 ± 0.10
-259	158.34 ± 1.02	3.53 ± 0.10
-260	164.69 ± 1.02	3.53 ± 0.10
-261	171.04 ± 1.02	3.53 ± 0.10
-262	177.39 ± 1.02	3.53 ± 0.10
-263	183.74 ± 1.14	3.53 ± 0.10
-264	190.09 ± 1.14	3.53 ± 0.10
-265	196.44 ± 1.14	3.53 ± 0.10
-266	202.79 ± 1.14	3.53 ± 0.10
-267	209.14 ± 1.27	3.53 ± 0.10
-268	215.49 ± 1.27	3.53 ± 0.10
-269	221.84 ± 1.27	3.53 ± 0.10
-270	228.19 ± 1.27	3.53 ± 0.10
-271	234.54 ± 1.40	3.53 ± 0.10
-272	240.89 ± 1.40	3.53 ± 0.10
-273	247.24 ± 1.40	3.53 ± 0.10
-274	253.59 ± 1.40	3.53 ± 0.10
-275	266.29 ± 1.40	3.53 ± 0.10
-276	278.99 ± 1.65	3.53 ± 0.10
-277	291.69 ± 1.65	3.53 ± 0.10
-278	304.39 ± 1.65	3.53 ± 0.10
-279	329.79 ± 1.65	3.53 ± 0.10
-280	355.19 ± 1.65	3.53 ± 0.10
-281	—	3.53 ± 0.10
-282	405.26 ± 1.91	3.53 ± 0.10
-283	430.66 ± 2.03	3.53 ± 0.10
-284	456.06 ± 2.16	3.53 ± 0.10
-309	10.46 ± 0.13	5.33 ± 0.13
-310	12.07 ± 0.13	5.33 ± 0.13
-311	13.64 ± 0.18	5.33 ± 0.13
-312	15.24 ± 0.23	5.33 ± 0.13
-313	16.81 ± 0.23	5.33 ± 0.13
-314	18.42 ± 0.25	5.33 ± 0.13
-315	19.99 ± 0.25	5.33 ± 0.13
-316	21.59 ± 0.25	5.33 ± 0.13
-317	23.16 ± 0.25	5.33 ± 0.13
-318	24.77 ± 0.25	5.33 ± 0.13
-319	26.34 ± 0.25	5.33 ± 0.13
-320	27.94 ± 0.30	5.33 ± 0.13
-321	29.51 ± 0.30	5.33 ± 0.13
-322	31.12 ± 0.30	5.33 ± 0.13
-323	32.69 ± 0.30	5.33 ± 0.13
-324	34.29 ± 0.30	5.33 ± 0.13
-325	37.47 ± 0.38	5.33 ± 0.13
-326	40.64 ± 0.38	5.33 ± 0.13
-327	43.82 ± 0.38	5.33 ± 0.13
-328	46.99 ± 0.38	5.33 ± 0.13
-329	50.17 ± 0.46	5.33 ± 0.13
-330	53.34 ± 0.46	5.33 ± 0.13
-331	56.52 ± 0.46	5.33 ± 0.13
-332	59.69 ± 0.46	5.33 ± 0.13
-333	62.87 ± 0.51	5.33 ± 0.13
-334	66.04 ± 0.51	5.33 ± 0.13
-335	69.22 ± 0.51	5.33 ± 0.13
-336	72.39 ± 0.51	5.33 ± 0.13
-337	75.57 ± 0.61	5.33 ± 0.13
-338	78.74 ± 0.61	5.33 ± 0.13
-339	81.92 ± 0.61	5.33 ± 0.13
-340	85.09 ± 0.61	5.33 ± 0.13
-341	88.27 ± 0.61	5.33 ± 0.13
-342	91.44 ± 0.71	5.33 ± 0.13
-343	94.62 ± 0.71	5.33 ± 0.13
-344	97.79 ± 0.71	5.33 ± 0.13
-345	100.97 ± 0.71	5.33 ± 0.13
-346	104.14 ± 0.71	5.33 ± 0.13
-347	107.32 ± 0.76	5.33 ± 0.13
-348	110.49 ± 0.76	5.33 ± 0.13
-349	113.67 ± 0.76	5.33 ± 0.13
-350	116.84 ± 0.76	5.33 ± 0.13
-351	120.02 ± 0.76	5.33 ± 0.13
-352	123.19 ± 0.76	5.33 ± 0.13
-353	126.37 ± 0.94	5.33 ± 0.13
-354	129.54 ± 0.94	5.33 ± 0.13
-355	132.72 ± 0.94	5.33 ± 0.13
-356	135.89 ± 0.94	5.33 ± 0.13
-357	139.07 ± 0.94	5.33 ± 0.13
-358	142.24 ± 0.94	5.33 ± 0.13
-359	145.42 ± 0.94	5.33 ± 0.13
-360	148.59 ± 0.94	5.33 ± 0.13
-361	151.77 ± 0.94	5.33 ± 0.13
-362	158.12 ± 1.02	5.33 ± 0.13
-363	164.47 ± 1.02	5.33 ± 0.13
-364	170.82 ± 1.02	5.33 ± 0.13
-365	177.17 ± 1.02	5.33 ± 0.13
-366	183.52 ± 1.14	5.33 ± 0.13
-367	189.87 ± 1.14	5.33 ± 0.13
-368	196.22 ± 1.14	5.33 ± 0.13
-369	202.57 ± 1.14	5.33 ± 0.13
-370	208.92 ± 1.27	5.33 ± 0.13
-371	215.27 ± 1.27	5.33 ± 0.13
-372	221.62 ± 1.27	5.33 ± 0.13
-373	227.97 ± 1.27	5.33 ± 0.13
-374	234.32 ± 1.40	5.33 ± 0.13
-375	240.67 ± 1.40	5.33 ± 0.13
-376	247.02 ± 1.40	5.33 ± 0.13
-377	253.37 ± 1.40	5.33 ± 0.13
-378	266.07 ± 1.52	5.33 ± 0.13
-379	278.77 ± 1.52	5.33 ± 0.13
-380	291.47 ± 1.65	5.33 ± 0.13
-381	304.17 ± 1.65	5.33 ± 0.13
-382	329.57 ± 1.65	5.33 ± 0.13
-383	354.97 ± 1.78	5.33 ± 0.13
-384	380.37 ± 1.78	5.33 ± 0.13
-385	405.26 ± 1.91	5.33 ± 0.13
-386	430.66 ± 2.03	5.33 ± 0.13
-387	456.06 ± 2.16	5.33 ± 0.13
-388	481.46 ± 2.29	5.33 ± 0.13
-389	506.86 ± 2.41	5.33 ± 0.13
-390	532.26 ± 2.41	5.33 ± 0.13
-391	557.66 ± —	5.33 ± 0.13
-392	582.68 ± 2.67	5.33 ± 0.13
-393	608.08 ± 2.79	5.33 ± 0.13
-394	633.48 ± 2.92	5.33 ± 0.13
-395	658.88 ± 3.05	5.33 ± 0.13
-425	113.67 ± 0.84	6.99 ± 0.15
-426	116.84 ± 0.84	6.99 ± 0.15
-427	120.02 ± 0.84	6.99 ± 0.15
-428	—	6.99 ± 0.15
-429	126.37 ± 0.94	6.99 ± 0.15
-430	129.54 ± 0.94	6.99 ± 0.15
-431	132.72 ± 0.94	6.99 ± 0.15
-432	—	6.99 ± 0.15
-433	139.07 ± 0.94	6.99 ± 0.15
-434	142.24 ± 0.94	6.99 ± 0.15
-435	145.42 ± 0.94	6.99 ± 0.15
-436	—	6.99 ± 0.15
-437	151.77 ± 0.94	6.99 ± 0.15
-438	158.12 ± 1.02	6.99 ± 0.15
-439	164.47 ± 1.02	6.99 ± 0.15
-440	170.82 ± 1.02	6.99 ± 0.15
-441	177.17 ± 1.02	6.99 ± 0.15
-442	183.52 ± 1.14	6.99 ± 0.15
-443	189.87 ± 1.14	6.99 ± 0.15
-444	196.22 ± 1.14	6.99 ± 0.15
-445	202.57 ± 1.14	6.99 ± 0.15
-446	215.27 ± 1.40	6.99 ± 0.15
-447	227.97 ± 1.40	6.99 ± 0.15
-448	240.67 ± 1.40	6.99 ± 0.15
-449	—	6.99 ± 0.15
-450	266.07 ± 1.52	6.99 ± 0.15
-451	278.77 ± 1.52	6.99 ± 0.15
-452	291.47 ± 1.52	—
-453	304.17 ± 1.52	6.99 ± 0.15
-454	316.87 ± 1.52	6.99 ± 0.15
-455	329.57 ± 1.52	6.99 ± 0.15
-456	342.27 ± 1.78	6.99 ± 0.15
-457	354.97 ± 1.78	6.99 ± 0.15
-458	367.67 ± 1.78	6.99 ± 0.15
-459	380.37 ± 1.78	6.99 ± 0.15
-460	393.07 ± 1.78	6.99 ± 0.15
-461	405.26 ± 1.91	6.99 ± 0.15
-462	417.96 ± 1.91	6.99 ± 0.15
-463	430.66 ± 2.03	6.99 ± 0.15
-464	443.36 ± 2.16	6.99 ± 0.15
-465	456.06 ± 2.16	6.99 ± 0.15
-466	468.76 ± 2.16	6.99 ± 0.15
-467	481.46 ± 2.29	6.99 ± 0.15
-468	494.16 ± 2.29	6.99 ± 0.15
-469	506.86 ± 2.41	6.99 ± 0.15
-470	532.26 ± 2.41	6.99 ± 0.15
-471	557.66 ± 2.54	6.99 ± 0.15
-472	582.68 ± 2.67	6.99 ± 0.15
-473	608.08 ± 2.79	6.99 ± 0.15
-474	633.48 ± 2.92	6.99 ± 0.15
-475	658.88 ± 3.05	6.99 ± 0.15
-901	4.70 ± 0.13	1.42 ± 0.08
-902	6.07 ± 0.13	1.63 ± 0.08
-903	7.65 ± 0.13	1.63 ± 0.08
-904	8.92 ± 0.13	1.83 ± 0.08
-905	10.52 ± 0.13	1.83 ± 0.08
-906	11.89 ± 0.13	1.98 ± 0.08
-907	13.46 ± 0.18	2.08 ± 0.08
-908	16.36 ± 0.23	2.21 ± 0.08
-909	17.93 ± 0.23	2.46 ± 0.08
-910	19.18 ± 0.23	2.46 ± 0.08
-911	21.92 ± 0.23	2.95 ± 0.10
-912	23.47 ± 0.23	2.95 ± 0.10
-913	25.04 ± —	2.95 ± 0.10
-914	26.59 ± —	2.95 ± 0.10
-916	29.74 ± —	2.95 ± 0.10
-918	34.42 ± 0.30	2.95 ± 0.10
-920	37.47 ± 0.36	3.00 ± 0.10
-924	43.69 ± 0.36	3.00 ± 0.10
-928	53.09 ± 0.46	3.00 ± 0.10
-932	59.36 ± —	3.00 ± 0.10

The same rings in millimeters, ± tolerance. A dash: our sources round it differently or differ.

O-ring material names
Listed as	Is
Buna-N	nitrile
Viton	fluorocarbon (FKM)

The dash number sets the size only; the compound and its hardness (durometer) are the maker’s, listed with each part.

Good to know

Order by the dash number, check by the actual size. The nominal fractions are only the size’s name: a -010 is called 1/4 × 3/8 × 1/16 but measures .239″ inside and .070″ across. To identify a ring, measure its cross-section first — a used ring stretches and swells, so its ID can read off.

Size and material are separate choices. Buna-N is nitrile; Viton is fluorocarbon (FKM). The groove, squeeze and compound for a job are the equipment maker’s call; the dimensions here are the AS568 sizes as the makers publish them. Sizes -400 to -424 (the 400 series “extended” sizes) are in only one of our sources and are left off.

Quick answers

What size is a -010 O-ring?: An AS568 -010 is .239″ ID × .070″ W (actual, ±.005″ / ±.003″); its nominal size is 1/4 × 3/8 × 1/16″.
What does the AS568 dash number mean?: It names one O-ring size. The first digit is the cross-section series — -0xx series 1/16″ (.070″), -1xx series 3/32″ (.103″), -2xx series 1/8″ (.139″), -3xx series 3/16″ (.210″), -4xx series 1/4″ (.275″) — and the rest steps up the inside diameter.
What are the dimensions of a 214 O-ring?: AS568 -214: ID .984″ ± .010″, cross-section .139″ ± .004″.
What O-ring fits a 1/2 inch tube fitting boss?: An AS568 -908 (900 series boss gasket for 1/2″ OD tube): .644″ ID × .087″ W.
Is a 1/4 x 3/8 x 1/16 O-ring really 1/4 inch inside?: No. Those fractions are the nominal size (the name). The -010 that carries it measures .239″ inside and .070″ across the cross-section.

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