Structural Flat Washer Flat Washer Type Standard Material Stainless Steel Material Grade/Class 316 Finish Plain For Screw Size 1/2 in Inside Diameter 0.531 in Outside Diameter 1 1/16 in Maximum Thickness 0.203 in System of Measurement Inch Minimum Thickness 0.203 in Inside Diameter Tolerance +/-0.010 in Material Quality Standards ASTM A276 Outside Diameter Tolerance +/-0.010 in Pack Size Small Pack Resistance Properties Corrosion Resistant Saltwater Resistant Solvent Resistant