Internal Hex, Internal Torx, External Hex, TX, Hex
Metric, AF, Torx, Imperial, SAE
5.5 mm, 1/4 ", 9/16 ", 1-1/2 ", 11/16 "
1/4, 3/4, 1-1/2, 2-1/2, 3/8
6.35, 9.53, 19.05, 38.1, 25.4
Special Steel, Molybdenum Steel, Alloy Steel, Steel, Chrome Molybdenum Alloy Steel
Gun-metal, Phosphated, Oxidised, Black Phosphate, Black Oxide