Lock Washer, Lock Washer Type Internal Tooth Lock, Finish Zinc Plated, Material Steel, For Screw Size M12, Inside Diameter 12.5 mm, Outside Diameter 20.5 mm, Maximum Thickness 1 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 50