Flat Washer, Dimensional Standards AMPG 2001 FL.01, Material Steel, Material Grade/Class Case Hardened, Finish Plain, For Screw Size 1 1/4 in, Inside Diameter 1.281 in, Outside Diameter 2 1/4 in, Maximum Thickness 5/16 in, System of Measurement Inch, Minimum Thickness 5/16 in, Made in North America Made in North America, Material Quality Standards ASTM A108