Internal Hex, External Hex, Internal Torx, TX, Hex
AF, Imperial, Torx, SAE, Metric
4 mm, 5/16 ", 13/16 ", 7/8 ", 9/16 "
25.4, 6.35, 19.05, 9.53, 38.1
Special Steel, Molybdenum Steel, Alloy Steel, Steel, Chrome Molybdenum Alloy Steel
Phosphatized, Gun-metal, Oxidised, Black Phosphate, Black Oxide