Spherical Washer Bottom Washer Inside Diameter 23.2 mm Bottom Washer Outside Diameter 36 mm Bottom Washer Radius 27 mm Finish Plain For Screw Size M20 Material Stainless Steel Material Grade/Class 18-8 Maximum Thickness 11.7 mm Minimum Thickness 11.7 mm Pack Size Small Pack Rockwell Hardness B83 to B95 Spherical Washer Type Spherical Washer Assembly System of Measurement Metric Top Washer Inside Diameter 21 mm Top Washer Outside Diameter 36 mm 1 Pair