External Hex, Internal Hex, Internal Torx, TX, Hex
Torx, AF, Imperial, SAE, Metric
5/16 ", 5.5 mm, 5/8 ", 9 mm, 25 mm
38.1, 9.53, 19.05, 6.35, 25.4
Special Steel, Molybdenum Steel, Alloy Steel, Steel, Chrome Molybdenum Alloy Steel
Phosphated, Gun-metal, Oxidised, Black Phosphate, Black Oxide