Internal Hex, External Hex, Internal Torx, TX, Hex
Imperial, AF, Metric, Torx, SAE
4.5 mm, 9/16 ", 11/16 ", 5/16 ", 7/16 "
1, 1-1/2, 2-1/2, 3/8, 1/2
38.1, 12.5, 6.35, 9.53, 19.05
Special Steel, Molybdenum Steel, Alloy Steel, Steel, Chrome Molybdenum Alloy Steel
Phosphatized, Gun-metal, Oxidised, Black Phosphate, Black Oxide