Flat Washer, Flat Washer Type Oversized, Dimensional Standards ASME B18.21.1, Material Steel, Material Grade/Class Case Hardened, Finish Zinc-Plated, For Screw Size 5/16 in, Inside Diameter 0.344 in, Outside Diameter 2 in, Maximum Thickness 1/8 in, System of Measurement Inch, Minimum Thickness 1/8 in, Color Silver, Inside Diameter Tolerance 0.339-0.359, Made in North America Not Made in North America, Manufacturer Location Globally Sourced, Material Quality Standards Not Rated