Internal Hex, External Hex, Internal Torx, Hex, TX
AF, Imperial, Torx, SAE, Metric
3/16 ", 5.5 mm, 5/16 ", 5/8 ", 10 mm
1, 1-1/2, 1/4, 2-1/2, 1/2
19.05, 38.1, 12.5, 9.53, 25.4
Special Steel, Molybdenum Steel, Alloy Steel, Steel, Chrome Molybdenum Alloy Steel
Phosphatized, Phosphated, Oxidised, Black Phosphate, Black Oxide