Split Lock Washer Lock Washer Type Split Lock Finish Black Oxide Material Steel For Screw Size 1 1/4 in Inside Diameter 1.28 in Outside Diameter 1.79 in Maximum Thickness 0.313 in Minimum Thickness 0.313 in Dimensional Standards ASME B18.21.1 Material Grade/Class Not Graded Pack Size Small Pack Resistance Properties Vibration Resistant Rockwell Hardness C46 System of Measurement Inch Package Quantity 10