Lock Washer Lock Washer Type Internal Tooth Lock Finish Zinc Plated Material Spring Steel For Screw Size M18 Inside Diameter 19 mm Outside Diameter 30 mm Maximum Thickness 1.4 mm Color Silver Dimensional Standards DIN 6798 J Material Grade/Class Not Graded Material Quality Standards 350-425 HV10 Pack Size Small Pack System of Measurement Metric Package Quantity 50