Internal Hex, Internal Torx, External Hex, TX, Hex
AF, Imperial, Torx, Metric, SAE
5.5 mm, 19 mm, 5/8 ", 11/16 ", 9 mm
38.1, 25.4, 6.35, 19.05, 9.53
Special Steel, Molybdenum Steel, Alloy Steel, Steel, Chrome Molybdenum Alloy Steel
Phosphatized, Gun-metal, Oxidised, Black Phosphate, Black Oxide