External Hex, Internal Torx, Internal Hex, TX, Hex
Imperial, Metric, Torx, AF, SAE
7/8 ", 5 mm, 5/16 ", 11/16 ", 1-1/2 "
38.1, 19.05, 9.53, 6.35, 25.4
Special Steel, Molybdenum Steel, Alloy Steel, Steel, Chrome Molybdenum Alloy Steel
Phosphatized, Phosphated, Oxidised, Black Phosphate, Black Oxide