External Hex, Internal Hex, TX, Hex, External Torx
Imperial, AF, Torx, SAE, Metric
5.5 mm, 8 mm, 5 mm, 5/16 ", 5/8 "
38.1, 19.05, 12.5, 9.53, 6.35
Special Steel, Molybdenum Steel, Alloy Steel, Steel, Chrome Molybdenum Alloy Steel
Gun-metal, Phosphatized, Oxidised, Black Phosphate, Black Oxide