Flat Washer Flat Washer Type Standard Dimensional Standards ASME B18.22.1 Material Stainless Steel Material Grade/Class 316 Finish NL-19 For Screw Size 1/4 in Inside Diameter 0.281 in Outside Diameter 5/8 in Maximum Thickness 0.065 in System of Measurement Inch Minimum Thickness 0.065 in Color Silver Pack Size Small Pack Resistance Properties Corrosion Resistant Rockwell Hardness B80 Thickness Tolerance +/-0.015 in Package Quantity 50