Internal Hex, Internal Torx, External Hex, Hex, TX
Metric, Imperial, AF, Torx, SAE
5.5 mm, 12 mm, 3/16 ", 5/16 ", 1-1/2 "
38.1, 19.05, 25.4, 6.35, 9.53
Special Steel, Molybdenum Steel, Alloy Steel, Steel, Chrome Molybdenum Alloy Steel
Phosphated, Gun-metal, Oxidised, Black Phosphate, Black Oxide