6063 is a heat treatable alloy with manganese and silicon as its principal alloying elements. It has not quite the strength of 6061, but good resistance to atmospheric corrosion. It is readily workable and has excellent finishing characteristics

Square tube is an efficient member with many inherent advantages, including strength and lightness. For example, for a given weight the square distributes stresses in compression and vertical loading equally and in all directions. In torsion it is capable of carrying a greater load than any other structural member of equal weight