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