Lock Washer Lock Washer Type External Tooth Lock Finish Plain Material Stainless Steel For Screw Size M12 Inside Diameter 13 mm Outside Diameter 20.5 mm Maximum Thickness 1 mm Dimensional Standards DIN 6798 A Material Grade/Class 18-8 Pack Size Small Pack Rockwell Hardness C38 to C46 System of Measurement Metric Package Quantity 25