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 0.313 in Outside Diameter 3/4 in Maximum Thickness 0.16 in System of Measurement Inch Minimum Thickness 0.108 in Color Silver Pack Size Small Pack Resistance Properties Corrosion Resistant Rockwell Hardness B70 Thickness Tolerance +0.051 to 0.080 in Package Quantity 25