USS Washer Flat Washer Type USS Dimensional Standards ASME B18.22.1 Material Steel Material Grade/Class Grade 2 Finish Zinc Yellow For Screw Size 3/8 in Inside Diameter 0.438 in Outside Diameter 1 in Maximum Thickness 0.084 in System of Measurement Inch Minimum Thickness 0.084 in Color Yellow Pack Size Bulk Pack Rockwell Hardness RC38 Thickness Tolerance +/-0.020 in Package Quantity 3700