Spherical Flange Nut, Material Grade/Class 18-8, Material Stainless Steel, Finish Black Oxide, Thread Size 1/4 In.-20, Hex Width 1/2 in, Hex Height 7/32 in, Flange Diameter 1 5/8 in, System of Measurement Inch, Compatible Washer Manufacturer Part Number 47741, Maximum Rotation 5 Degrees , Nut Finish Plain, Pack Size Small Pack, Rockwell Hardness 27 Rockwell