Split Lock Washer Lock Washer Type Split Lock Finish Black Oxide Material Steel For Screw Size M20 Inside Diameter 20.2 mm Outside Diameter 33.6 mm Maximum Thickness 4 mm Minimum Thickness 4 mm Color Black Dimensional Standards DIN 127 B Inside Diameter Tolerance +/-0.127 mm Made in North America No Manufacturer Location Globally Sourced Material Grade/Class Not Graded Material Quality Standards ASTM A307A SAE J429 Maximum Temperature 275 Degrees F