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 #6 Inside Diameter 0.156 in Outside Diameter 5/16 in Maximum Thickness 0.047 in System of Measurement Inch Minimum Thickness 0.047 in Color Silver Inside Diameter Tolerance 0.151-0.164 Made in North America No Manufacturer Location Globally Sourced Material Quality Standards Not Rated Maximum Temperature 350 Degrees C