Thick Washer Flat Washer Type Standard Material Steel Material Grade/Class Grade 5 Finish Black Oxide For Screw Size M8 Inside Diameter 8.4 mm Outside Diameter 16 mm Maximum Thickness 3 mm System of Measurement Metric Minimum Thickness 3 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 Package Quantity 10