Internal Hex, External Hex, Internal Torx, Hex, TX
Imperial, Torx, AF, SAE, Metric
3/16 ", 5.5 mm, 7/16 ", 1-1/2 ", 11/16 "
6.35, 9.53, 19.05, 25.4, 12.5
Special Steel, Molybdenum Steel, Alloy Steel, Steel, Chrome Molybdenum Alloy Steel
Gun-metal, Phosphated, Oxidised, Black Oxide, Black Phosphate