Flat Washer Flat Washer Type Standard Dimensional Standards ANSI B18.22.1 Material Stainless Steel Material Grade/Class 316 Finish NL-19 For Screw Size 5/16 in Inside Diameter 0.375 in Outside Diameter 7/8 in Maximum Thickness 0.065 in System of Measurement Inch Minimum Thickness 0.036 in Color Silver Pack Size Small Pack Resistance Properties Corrosion Resistant Rockwell Hardness B80 Thickness Tolerance +0.064 to 0.104 in Package Quantity 100