Internal Hex, Internal Torx, External Hex, TX, Hex
Imperial, AF, Metric, Torx, SAE
5/16 ", 5/8 ", 5 mm, 9/16 ", 3/16 "
1-1/2, 1/4, 2-1/2, 1/2, 3/8
38.1, 19.05, 9.53, 6.35, 25.4
Special Steel, Molybdenum Steel, Alloy Steel, Steel, Chrome Molybdenum Alloy Steel
Phosphatized, Gun-metal, Oxidised, Black Phosphate, Black Oxide