Extra Thick Washer Flat Washer Type Standard Material Steel Material Grade/Class Grade 5 Finish Black Oxide For Screw Size M36 Inside Diameter 37 mm Outside Diameter 50 mm Maximum Thickness 7.5 mm System of Measurement Metric Minimum Thickness 7.5 mm Color Black Inside Diameter Tolerance +/-0.010 in Outside Diameter Tolerance +/-0.010 in Pack Size Small Pack Rockwell Hardness C4 Thickness Tolerance +0.40mm/-0.50mm