Flat Washer, Dimensional Standards AMPG 2001 FL.01, Material Steel, Material Grade/Class Case Hardened, Finish Black Oxide, For Screw Size #4, Inside Diameter 0.125 in, Outside Diameter 3 in, Maximum Thickness 1/16 in, System of Measurement Inch, Minimum Thickness 1/16 in, Color Black, Made in North America Made in North America, Material Quality Standards ASTM A108