Spherical Washer Bottom Washer Inside Diameter 14.2 mm Bottom Washer Outside Diameter 24 mm Bottom Washer Radius 17 mm Finish Black Oxide For Screw Size M12 Material Steel Maximum Thickness 8 mm Minimum Thickness 8 mm Pack Size Small Pack Rockwell Hardness C40 Spherical Washer Type Spherical Washer Assembly System of Measurement Metric Top Washer Inside Diameter 13 mm Top Washer Outside Diameter 24 mm 1 Pair