Flat Washer Flat Washer Type Oversized Dimensional Standards ASME B18.22.1 Material Steel Material Grade/Class Class 8.8 Finish Black Oxide For Screw Size 5/16 in Inside Diameter 0.344 in Outside Diameter 3/4 in Maximum Thickness 0.125 in System of Measurement Inch Minimum Thickness 0.125 in Color Clear Inside Diameter Tolerance 0.339-0.359 Made in North America No Manufacturer Location Globally Sourced Material Quality Standards ASTM A-325 Maximum Temperature 350 Degrees C