Lock Nut, Finish Zinc Plated, Material Steel, Material Grade/Class Grade 2, Thread Size 5/8 In.-18, Hex Width 15/16 in, Hex Height 25/64 in, Lock Type Nylon Insert, System of Measurement Inch, Hex Type Standard Hex, Thread Direction Right Hand, Insert Material Nylon, Maximum Temperature 250 Degrees F, Pack Size Small Pack, Rockwell Hardness C28 Max., Package Quantity 50