Hardened Steel Washer Flat Washer Type Standard Dimensional Standards ASTM F436 Material Steel Material Grade/Class Grade 8 Finish Black Oxide For Screw Size 5/8 in Inside Diameter 0.688 in Outside Diameter 1 5/16 in Maximum Thickness 0.177 in System of Measurement Inch Minimum Thickness 0.122 in Color Black Inside Diameter Tolerance -0 to +0.03125 in Made in North America No Manufacturer Location Globally Sourced Material Quality Standards ASTM F436