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