Lock Washer Lock Washer Type Internal Tooth Lock Finish Zinc Plated Material Steel For Screw Size M5.1 Inside Diameter 5.1 mm Outside Diameter 9 mm Maximum Thickness 0.5 mm Dimensional Standards DIN 6798 J Material Grade/Class Not Graded Pack Size Small Pack Rockwell Hardness C38 to C46 System of Measurement Metric Package Quantity 100