This specification covers an aluminum alloy in the form of extruded rods, bars, and profiles (shapes) produced with thickness between 0.040 and 2.500 inches (1.02 to 38.10 mm) in thickness, and having a maximum cross sectional area of 23 in² (15000 mm²) and a maximum circumscribing circle diameter (circle size) of 16 inches (406 mm) (see 8.4.1).