Split Lock Washer Finish Black Oxide Material Steel For Screw Size 1/4 in Inside Diameter 0.252 in Outside Diameter 0.533 in Maximum Thickness 0.084 in Minimum Thickness 0.084 in Dimensional Standards ASME B18.21.1 Material Grade/Class Not Graded Pack Size Small Pack Rockwell Hardness C40 to C50 Package Quantity 100