Plain Washer Flat Washer Type Standard Dimensional Standards DIN 433 Material Steel Material Grade/Class Grade 2 Finish Zinc Plated For Screw Size M20 Inside Diameter 21 mm Outside Diameter 34 mm Maximum Thickness 3 mm System of Measurement Metric Minimum Thickness 3 mm Maximum Temperature 302 Degrees F Minimum Temperature -58 Degrees F Pack Size Small Pack Package Quantity 100