Lock Washer, Carbon Steel, Carbon Steel, Finish Zinc Plated, Fits Bolt Sizes 16mm, M16, Inside Dia. 16.6 mm, Outside Dia. 25.4 mm, Thickness 4.74 mm, Thickness Tolerance +/- 0.28 mm, Color Gray, Rockwell Hardness C46, Helps Prevent Loosening, For Use With Bolts, Package Quantity 100. This item has been restricted from sale in the following state (s): []