Internal Hex, External Hex, Internal Torx, TX, Hex
Imperial, AF, Metric, Torx, SAE
5.5 mm, 13/16 ", 5/16 ", 9/16 ", 11 mm
1, 1-1/2, 2-1/2, 1/2, 3/8
19.05, 12.5, 6.35, 38.1, 9.53
Special Steel, Molybdenum Steel, Alloy Steel, Steel, Chrome Molybdenum Alloy Steel
Gun-metal, Phosphated, Oxidised, Black Phosphate, Black Oxide