Square Washer, Dimensional Standards AMPG 2017 SQ.01, Material Steel, Material Grade/Class Case Hardened, Finish Black Oxide, For Screw Size 3/4 in, Inside Diameter 0.812 in, Outside Diameter Not Applicable, Maximum Thickness 17/64 in, System of Measurement Inch, Minimum Thickness 15/64 in, Color Black, Material Quality Standards ASTM A108, Pack Size Small Pack, Resistance Properties Corrosion-Resistant, Rockwell Hardness C40, Thickness Tolerance +/-0.030 in