Internal Hex, Internal Torx, External Hex, Hex, TX
Imperial, AF, Metric, Torx, SAE
5/16 ", 7/8 ", 12 mm, 5/8 ", 3/4 "
1-1/2, 2-1/2, 3/8, 1/2, 1
19.05, 6.35, 25.4, 12.5, 9.53
Special Steel, Molybdenum Steel, Alloy Steel, Steel, Chrome Molybdenum Alloy Steel
Phosphatized, Gun-metal, Oxidised, Black Phosphate, Black Oxide