Internal Hex, Internal Torx, External Hex, Hex, TX
AF, Torx, Metric, Imperial, SAE
3/8 ", 5.5 mm, 5/16 ", 5/8 ", 1-1/2 "
6.35, 25.4, 19.05, 9.53, 38.1
Special Steel, Molybdenum Steel, Alloy Steel, Steel, Chrome Molybdenum Alloy Steel
Gun-metal, Phosphated, Oxidised, Black Phosphate, Black Oxide