Flange Nut Material Grade/Class Not Graded Material Steel Finish Black Oxide Thread Size 1/4 In.-28 Hex Width 1/2 in Hex Height 5/16 in Flange Diameter 5/8 in System of Measurement Inch Color Black Flange Thickness 0.094 in Hex Type Flange Nut Overall Height 5/16 in Pack Size Small Pack Rockwell Hardness 85-90 Rockwell on 15N Scale Thread Direction Right Hand