Lock Nut, Finish Black Oxide, Material Steel, Material Grade/Class Grade 8, Thread Size 1/4 In.-20, Hex Width 7/16 in, Hex Height 5/16 in, Lock Type Nylon Insert, Dimensional Standards ASME B18.16.6, System of Measurement Inch, Hex Type Standard Hex, Thread Direction Right Hand, Pack Size Small Pack, Rockwell Hardness HRC24 - C32, Package Quantity 100