Internal Hex, Internal Torx, External Hex, Hex, TX
Imperial, AF, Metric, Torx, SAE
9/16 ", 11 mm, 18 mm, 5/16 ", 5/8 "
2-1/2, 1-1/2, 3/4, 3/8, 1/2
9.53, 25.4, 19.05, 12.5, 38.1
Special Steel, Molybdenum Steel, Alloy Steel, Steel, Chrome Molybdenum Alloy Steel
Gun-metal, Phosphated, Oxidised, Black Phosphate, Black Oxide