A round washer with notches formed into its outer edge, protrusions equally spaced from each other on the top face and
corresponding pockets on the bottom face.

These washers are designed to be used with A325 structural bolts. The washer is placed beneath the head of the bolt and as the bolt
is tightened, the protrusions compress. When the protrusions have been flattened a sufficient amount the fastening has achieved the
proper tension. Direct tension indicators are not affected by the presence of oil or other lubricants, and they measure tension
regardless of surface condition. They help ensure proper tension is achieved even when a simple box wrench or socket wrench are the
only tools that can be used to tighten the screw.

Direct tension indicator washers shall be manufactured from a steel which conforms to the following chemical composition
requirements (product analysis): Carbon- 0.27-0.53%; Manganese- 0.47-0.93%; Phosphorous- 0.043% maximum;
Sulfur- 0.048% maximum; Silicon – 0.13-0.37%

Parts shall be through hardened by heating to a temperature above the upper transformation temperature, quenched in liquid, then
retempered by reheating to a suitable temperature to achieve the listed mechanical and performance requirements.