Internal Hex, Internal Torx, External Hex, Hex, TX
Imperial, Metric, Torx, AF, SAE
4.5 mm, 5.5 mm, 9/32 ", 5/16 ", 7/16 "
19.05, 38.1, 6.35, 9.53, 25.4
Special Steel, Molybdenum Steel, Alloy Steel, Steel, Chrome Molybdenum Alloy Steel
Gun-metal, Phosphated, Oxidised, Black Phosphate, Black Oxide