Internal Hex, Internal Torx, External Hex, TX, Hex
AF, Metric, Torx, Imperial, SAE
4 mm, 1 ", 13/16 ", 5.5 mm, 25 mm
19.05, 38.1, 9.53, 6.35, 25.4
Special Steel, Molybdenum Steel, Alloy Steel, Steel, Chrome Molybdenum Alloy Steel
Gun-metal, Phosphatized, Oxidised, Black Phosphate, Black Oxide