Split Lock Washer Finish Black Oxide Material Steel For Screw Size 3 in Inside Diameter 3.012 in Outside Diameter 4.16 in Maximum Thickness 0.526 in Minimum Thickness 0.526 in Dimensional Standards ASME B18.21.1 Material Grade/Class Not Graded Pack Size Small Pack Rockwell Hardness C40 to C50 Package Quantity 5