Internal Hex, Internal Torx, External Hex, TX, Hex
Imperial, AF, Torx, Metric, SAE
5.5 mm, 17 mm, 5/16 ", 23 mm, 11/16 "
1-1/2, 1, 3/8, 2-1/2, 3/4
9.53, 19.05, 6.35, 38.1, 25.4
Special Steel, Molybdenum Steel, Alloy Steel, Steel, Chrome Molybdenum Alloy Steel
Phosphatized, Gun-metal, Oxidised, Black Phosphate, Black Oxide