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