Internal Hex, External Hex, Internal Torx, TX, Hex
Imperial, AF, Metric, Torx, SAE
5.5 mm, 5/16 ", 7/16 ", 25 mm, 11/16 "
1-1/2, 3/8, 2-1/2, 1/2, 3/4
19.05, 25.4, 9.53, 12.5, 38.1
Special Steel, Molybdenum Steel, Alloy Steel, Steel, Chrome Molybdenum Alloy Steel
Phosphatized, Gun-metal, Oxidised, Black Phosphate, Black Oxide