USS Washer Flat Washer Type USS Dimensional Standards ASME B18.21.1 Material Steel Material Grade/Class Grade 2 Finish Hot Dipped Galvanized For Screw Size 3/8 in Inside Diameter 0.438 in Outside Diameter 1 in Maximum Thickness 0.078 in System of Measurement Inch Minimum Thickness 0.078 in Color Silver Inside Diameter Tolerance 0.433-0.453 Made in North America No Manufacturer Location Globally Sourced Material Quality Standards Not Rated Maximum Temperature 350 Degrees C