Internal Hex, Internal Torx, External Hex, Hex, TX
Imperial, Torx, AF, Metric, SAE
5/16 ", 7/16 ", 3/16 ", 5.5 mm, 13 mm
3/4, 1, 1-1/2, 3/8, 2-1/2
19.05, 25.4, 9.53, 6.35, 38.1
Special Steel, Molybdenum Steel, Alloy Steel, Steel, Chrome Molybdenum Alloy Steel
Gun-metal, Phosphatized, Oxidised, Black Phosphate, Black Oxide