Split Lock Washer, Finish Black Oxide, Material Steel, For Screw Size 1/2 in, Inside Diameter 0.502 in, Outside Diameter 0.879 in, Maximum Thickness 0.151 in, Minimum Thickness 0.151 in, Color Black, Dimensional Standards ASME B18.21.1, Material Grade/Class Not Graded, Pack Size Small Pack, Rockwell Hardness C38, System of Measurement Inch, Thickness Tolerance +0.010 in, Package Quantity 50