Split Lock Washer Lock Washer Type Split Lock Finish Black Oxide Material Steel For Screw Size M4 Inside Diameter 4.1 mm Outside Diameter 7.6 mm Maximum Thickness 0.9 mm Minimum Thickness 0.9 mm Dimensional Standards DIN 127 B Material Grade/Class Not Graded Pack Size Small Pack Rockwell Hardness C44 Thickness Tolerance +/-0.10 mm Package Quantity 100