Jam Nut, Hex Type Jam Hex, Finish Black Oxide, Material Steel, Material Grade/Class Grade A, Thread Size 5/16 In.-18, Hex Width 1/2 in, Hex Height 3/16 in, Dimensional Standards ASME B18.2.2, System of Measurement Inch, Thread Direction Right Hand, Pack Size Small Pack, Thread Type Coarse, Package Quantity 100