Internal Hex, External Hex, Internal Torx, Hex, TX
AF, Imperial, Torx, SAE, Metric
4 mm, 6 mm, 5/16 ", 5/8 ", 36 mm
6.35, 25.4, 9.53, 19.05, 12.5
Special Steel, Molybdenum Steel, Alloy Steel, Steel, Chrome Molybdenum Alloy Steel
Phosphated, Gun-metal, Oxidised, Black Phosphate, Black Oxide