Spherical Washer Assembly, Bottom Washer Inside Diameter 1.563 in, Bottom Washer Outside Diameter 2.875 in, Bottom Washer Radius 3 in, Dimensional Standards TCMAI, Finish Black Oxide, For Screw Size 1 1/2 in, Material Steel, Maximum Rotation 3 Degrees , Maximum Thickness 0.5 in, Minimum Thickness 0.5 in, Pack Size Small Pack, Rockwell Hardness 85 to 90 on 15N Scale, Spherical Washer Type Spherical Washer Assembly, System of Measurement Inch, Top Washer Inside Diameter 1.625 in