Split Lock Washer Finish Black Oxide Material Steel For Screw Size #4 Inside Diameter 0.114 in Outside Diameter 0.223 in Maximum Thickness 0.031 in Minimum Thickness 0.031 in Dimensional Standards ASME B18.21.1 Material Grade/Class Not Graded Pack Size Small Pack Rockwell Hardness C40 to C50 Package Quantity 100