'Spherical Washer, Low Carbon Steel, Black Oxide Finish, Fits Bolt Sizes 1/2 In, Inside Dia 17/32 In, Outside Dia 1 1/8 In, Thickness 5/16 In, Thickness Tolerance +/-0.010 In, Radius 1 1/2 In, Rockwell Hardness B49, For Use With Screws and Studs, Includes 1 Male Washers and 1 Female Washers'