USS Washer Flat Washer Type USS Dimensional Standards ASME B18.22.1 Material Steel Material Grade/Class Grade 2 Finish Zinc Plated For Screw Size 1/4 in Inside Diameter 0.313 in Outside Diameter 3/4 in Maximum Thickness 0.063 in System of Measurement Inch Minimum Thickness 0.063 in Color Silver Inside Diameter Tolerance 0.308-0.328 Made in North America No Manufacturer Location Globally Sourced Material Quality Standards Not Rated Maximum Temperature 350 Degrees C