Split Lock Washer Lock Washer Type Split Lock Finish Black Oxide Material Steel For Screw Size M18 Inside Diameter 18.2 mm Outside Diameter 29.4 mm Maximum Thickness 3.5 mm Minimum Thickness 3.5 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