Fender Washer Flat Washer Type Oversized Dimensional Standards ASME B18.22.1 Material Steel Material Grade/Class Grade 2 Finish Zinc Plated For Screw Size 1/4 in Inside Diameter 0.281 in Outside Diameter 1 in Maximum Thickness 0.052 in System of Measurement Inch Minimum Thickness 0.042 in Color Silver Inside Diameter Tolerance +/-0.010 in Outside Diameter Tolerance +/-0.010 in Pack Size Small Pack Rockwell Hardness B55 Thickness Tolerance +0.005/-0.004 in Package Quantity 50