External Hex, Internal Hex, Internal Torx, TX, Hex
Imperial, Metric, Torx, AF, SAE
5/16 ", 5/8 ", 18 mm, 7/16 ", 23 mm
1/2, 1-1/2, 3/4, 1/4, 2-1/2
9.53, 19.05, 38.1, 6.35, 25.4
Special Steel, Molybdenum Steel, Alloy Steel, Steel, Chrome Molybdenum Alloy Steel
Phosphatized, Gun-metal, Oxidised, Black Phosphate, Black Oxide