Slotted Washer Slotted Case Hardened Steel Finish Black Oxide Fits Bolt Sizes 1 In. Outside Dia 2-1/2 In. Thickness 7/16 In. Thickness Tolerance +/-0.015 In. Slot Width 1-1/32 In. Rockwell Hardness B49 For Use With For Easy Installation And Removal Without Removing Nut Assembly