Internal Hex, External Hex, Internal Torx, TX, Hex
AF, Metric, Imperial, Torx, SAE
7/16 ", 12 mm, 3/16 ", 15 mm, 5/16 "
38.1, 25.4, 9.53, 19.05, 6.35
Special Steel, Molybdenum Steel, Alloy Steel, Steel, Chrome Molybdenum Alloy Steel
Gun-metal, Phosphated, Oxidised, Black Phosphate, Black Oxide