Internal Hex, External Hex, Hex, TX, External Torx
Imperial, AF, Torx, SAE, Metric
11/32 ", 4.5 mm, 5/16 ", 7/16 ", 3/16 "
19.05, 6.35, 25.4, 38.1, 12.5
Special Steel, Molybdenum Steel, Alloy Steel, Steel, Chrome Molybdenum Alloy Steel
Gun-metal, Phosphatized, Oxidised, Black Phosphate, Black Oxide