Cap Nut, Profile High Crown, Material Grade/Class Not Graded, Material Steel, Finish Black Oxide, Thread Size 5/8 In.-18, Overall Height 1.281 in, Hex Width 15/16 in, Tensile Strength 70,000 psi, Dimensional Standards SAE J483, Material Quality Standards ASTM 12L14, System of Measurement Inch, Color Steel, Pack Size Small Pack, Rockwell Hardness B80 to B90, Thread Direction Right Hand, Package Quantity 2