Internal Hex, Internal Torx, External Hex, TX, Hex
AF, Imperial, Metric, Torx, SAE
15/16 ", 3/16 ", 5.5 mm, 5/16 ", 7/16 "
38.1, 6.35, 19.05, 9.53, 25.4
Special Steel, Molybdenum Steel, Alloy Steel, Steel, Chrome Molybdenum Alloy Steel
Gun-metal, Phosphated, Oxidised, Black Phosphate, Black Oxide