406 in, Bottom Washer Outside Diameter 0.25 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 0.438 in.25 in, Dimensional Standards TCMAI, Finish Black Oxide, For Screw Size 3/8 in, 5/16 in, Material Steel, Maximum Rotation 5 Degrees , Maximum Thickness 0.