Wedge Lock Washer Lock Washer Type Wedge Lock Finish Plain Material Stainless Steel For Screw Size M20 Inside Diameter 21.4 mm Outside Diameter 30.7 mm Assembly Thickness 3 mm Assembly Thickness Tolerance +/-0.25 mm Dimensional Standards DIN 25201 Material Grade/Class 316 Pack Size Small Pack Rockwell Hardness HRC52 System of Measurement Metric Package Quantity 100