Hex Nut, Hex Type Standard Hex, Finish Black Oxide, Material Grade/Class Grade 2, Material Steel, Thread Size 2 1/4 In.-4, Hex Width 3 1/2 in, Hex Height 2 1/2 in, System of Measurement Inch, Thread Direction Left Hand, Rockwell Hardness B85, Thread Pitch 0.25 in, Thread Type Acme