Flat Washer Flat Washer Type Standard Dimensional Standards ASME B18.22.1 Material Steel Material Grade/Class Grade 2 Finish Zinc Plated For Screw Size 1/2 in Inside Diameter 0.531 in Outside Diameter 1 1/4 in Maximum Thickness 0.109 in System of Measurement Inch Minimum Thickness 0.109 in Color Silver Inside Diameter Tolerance 0.526-0.546 Made in North America No Manufacturer Location Globally Sourced Material Quality Standards Not Rated Maximum Temperature 350 Degrees C