Internal Hex, External Hex, Internal Torx, TX, Hex
Imperial, AF, Torx, SAE, Metric
5.5 mm, 9/32 ", 11/16 ", 13/16 ", 5/16 "
1/4, 3/8, 1/2, 3/4, 2-1/2
38.1, 19.05, 6.35, 25.4, 9.53
Special Steel, Molybdenum Steel, Alloy Steel, Steel, Chrome Molybdenum Alloy Steel
Phosphated, Gun-metal, Oxidised, Black Phosphate, Black Oxide