Split Lock Washer Lock Washer Type Split Lock Finish Blue Phosphate Material Steel For Screw Size M20 Inside Diameter 21 mm Outside Diameter 32.5 mm Maximum Thickness 4.2 mm Minimum Thickness 4.2 mm Color Blue Dimensional Standards DIN 7980 Material Grade/Class Not Graded Pack Size Small Pack Rockwell Hardness HRC44 System of Measurement Metric Thickness Tolerance +/-0.200 mm Package Quantity 50