Size: M10 (I.D.: 9.2mm, O.D.: 20mm) Made of 65Mn Metal Steel, Anti-corrosion and Durable Great corrosion resistance for machinery equipment, easy to install Provide spring force, grip sturdy, create a permanent installation Widely used in machinery equipment, industrial production of shock absorption and insulation Uxcell high precision starlock push on locking washers Specification: Washer Type: Starlock Washer Material: 65Mn Spring Steel Finish: Black Oxide Size: M10 Fit Shaft Outer Diameter: 10mm Inner Diameter: 9.2mmm Outer Diameter: 20mm Thickness: 2.2mmm Package Content: 40pcs x Starlock Washer Description: Starlock Washer provides spring force between two attachments and grip shaft firmly in place. These push-on washers create a permanent installation and will lock firmly. 65Mn steel is a perfert material for spring washer due to its good strength. Black oxide finish gives better corrosion resistant performance in dry environments. Widely used in machinery equipment, industrial production of shock absorption, bearings, machinery, etc. The Starlock Washers have teeth that dig into the shaft material, so expect minor scratching.