Flat Washer Flat Washer Type Standard Dimensional Standards ASME B18.22.1 Material Stainless Steel Material Grade/Class 18-8 Finish Plain For Screw Size #12 Inside Diameter 0.25 in Outside Diameter 1/2 in Maximum Thickness 0.047 in System of Measurement Inch Minimum Thickness 0.047 in Pack Size Small Pack Package Quantity 50