Internal Hex, External Hex, TX, Hex, 6-Point
Metric, AF, Torx, Imperial, SAE
5.5 mm, 15/16 ", 5/16 ", 3/16 ", 5/8 "
19.05, 9.53, 25.4, 38.1, 6.35
Special Steel, Molybdenum Steel, Alloy Steel, Steel, Chrome Molybdenum Alloy Steel
Gun-metal, Phosphatized, Oxidised, Black Phosphate, Black Oxide