Split Lock Washer Lock Washer Type Split Lock Finish Black Oxide Material Steel For Screw Size #12 Inside Diameter 0.22 in Outside Diameter 0.377 in Maximum Thickness 0.056 in Minimum Thickness 0.056 in Dimensional Standards ASME B18.21.1 Material Grade/Class Not Graded Pack Size Small Pack Rockwell Hardness C40 to C50 Package Quantity 100