Flat Washer, Dimensional Standards AMPG 2001 FL.01, Material Steel, Material Grade/Class Case Hardened, Finish Black Oxide, For Screw Size 3/8 in, Inside Diameter 0.406 in, Outside Diameter 3/4 in, Maximum Thickness 3/32 in, System of Measurement Inch, Minimum Thickness 3/32 in, Color Black, Made in North America Made in North America, Material Quality Standards ASTM A108, Thickness Tolerance +0.005/-0.014 in