External Hex, Internal Hex, Internal Torx, TX, Hex
Imperial, Metric, AF, Torx, SAE
3/16 ", 5.5 mm, 5/16 ", 9/16 ", 1-1/2 "
3/4, 1-1/2, 1, 2-1/2, 1/2
9.53, 25.4, 19.05, 6.35, 38.1
Special Steel, Molybdenum Steel, Alloy Steel, Steel, Chrome Molybdenum Alloy Steel
Phosphated, Gun-metal, Oxidised, Black Phosphate, Black Oxide