Material: HARDENED STEEL Washer Type: Flat Outside Diameter (mm): 22.5 Inside Diameter (mm): 10.5 Fits Bolt Sizes (mm): M24 Thickness (mm): 36.35 Material Description: Hardened Steel Coating: None Inner Diameter (mm): 26 Outer Diameter (mm): 40 Thickness - 3 (mm): 8 Hardened: Yes Outside Diameter (OD) - 2 (mm): 40 Finish Notes: Caterpillar is changing from Zinc Plating to a Zinc Flake finish for many washers. The new coating improves corrosion protection to 720 hours. Until stock of the current finish is depleted, you may receive either finish due to the exhaust process. Inside Diameter (ID) - 1 (mm): 26 Finish: Zinc Flake