USS Washer Flat Washer Type USS Dimensional Standards ASME B18.22.1 Type A Wide USS Standard Material Steel Material Grade/Class Grade 2 Finish Zinc Plated For Screw Size 5/16 in Inside Diameter 0.375 in Outside Diameter 7/8 in Maximum Thickness 0.104 in System of Measurement Inch Minimum Thickness 0.064 in Pack Size Bulk Pack Resistance Properties Corrosion Resistant Rockwell Hardness 38HRC Thickness Tolerance +/-0.020 in Package Quantity 4350