Internal Hex, Internal Torx, External Hex, TX, Hex
AF, Imperial, Torx, Metric, SAE
5.5 mm, 5/8 ", 15 mm, 5/16 ", 25 mm
1-1/2, 3/8, 2-1/2, 3/4, 1
25.4, 6.35, 9.53, 12.5, 19.05
Special Steel, Molybdenum Steel, Alloy Steel, Steel, Chrome Molybdenum Alloy Steel
Phosphatized, Gun-metal, Oxidised, Black Phosphate, Black Oxide