Internal Hex, Internal Torx, External Hex, Hex, TX
AF, Torx, Imperial, SAE, Metric
5.5 mm, 5/16 ", 7/16 ", 11/16 ", 9 mm
1, 1-1/2, 2-1/2, 1/2, 3/8
9.53, 19.05, 25.4, 6.35, 38.1
Special Steel, Molybdenum Steel, Alloy Steel, Steel, Chrome Molybdenum Alloy Steel
Gun-metal, Phosphatized, Oxidised, Black Phosphate, Black Oxide