Fender Washer Flat Washer Type Oversized Material Stainless Steel Material Grade/Class 18-8 Finish Plain For Screw Size 1/2 in Inside Diameter 0.531 in Outside Diameter 1 1/2 in Maximum Thickness 0.073 in System of Measurement Inch Minimum Thickness 0.053 in Inside Diameter Tolerance +/-0.010 in Material Quality Standards ASTM A582 Outside Diameter Tolerance +/-0.010 in Pack Size Small Pack Resistance Properties Chemical Resistant Corrosion Resistant Rockwell Hardness B83