Type B Washer, Flat Washer Type Standard, Dimensional Standards ANSI B18.21.1, Material Steel, Material Grade/Class Case Hardened, Finish Zinc-Plated, For Screw Size 1 in, Inside Diameter 1.062 in, Outside Diameter 2 1/2 in, Maximum Thickness 11/64 in, System of Measurement Inch, Minimum Thickness 9/64 in, Color Silver, Inside Diameter Tolerance +/-0.010 in, Material Quality Standards ASTM A108, Outside Diameter Tolerance +/-0.010 in, Pack Size Small Pack, Rockwell Hardness B55