Diameter: 1/4Diameter 2: 31/64Thickness: 1/16Material: SteelFinish: ChromeHardness: Grade 8Nominal Size: 1/4 (#14)Style: Medium SplitType: Lock WasherApplication: Nuts and BoltsBox of 16.The purpose for a lock washer is to prevent threaded fasteners from loosening by creating friction between the fastener and the mounting surface.