Internal Hex, External Hex, TX, Hex, External Torx
Imperial, AF, Torx, Metric, SAE
11/16 ", 5/16 ", 7/16 ", 5.5 mm, 9/16 "
38.1, 19.05, 25.4, 6.35, 9.53
Special Steel, Molybdenum Steel, Alloy Steel, Steel, Chrome Molybdenum Alloy Steel
Gun-metal, Phosphated, Oxidised, Black Phosphate, Black Oxide