Internal Hex, Internal Torx, External Hex, TX, Hex
AF, Imperial, Metric, Torx, SAE
5/16 ", 7/16 ", 5.5 mm, 8 mm, 11/16 "
38.1, 25.4, 9.53, 19.05, 6.35
Special Steel, Molybdenum Steel, Alloy Steel, Steel, Chrome Molybdenum Alloy Steel
Phosphated, Gun-metal, Oxidised, Black Phosphate, Black Oxide