Internal Hex, Internal Torx, External Hex, Hex, TX
Imperial, Metric, AF, Torx, SAE
9/32 ", 4.5 mm, 5.5 mm, 3/16 ", 5/16 "
9.53, 6.35, 38.1, 19.05, 25.4
Special Steel, Molybdenum Steel, Alloy Steel, Steel, Chrome Molybdenum Alloy Steel
Gun-metal, Phosphatized, Oxidised, Black Phosphate, Black Oxide