USS Washer, Flat Washer Type USS, Dimensional Standards ASME B18.21.1, Material Steel, Material Grade/Class Through Hardened, Finish Zinc Yellow, For Screw Size 1/4 in, Inside Diameter 0.312 in, Outside Diameter 47/64 in, Maximum Thickness 5/64 in, System of Measurement Inch, Minimum Thickness 3/64 in, Color Yellow, Inside Diameter Tolerance 0.307-0.327, Made in North America Not Made in North America, Manufacturer Location Globally Sourced, Material Quality Standards ASTM A-325