The 5 aluminum tubes a 5 cm diameter fitted well into each other, they were protected outer surface / coated (?) And probably therefore specially packed individually in foil. A detailed German manual was, after more than 500 liters of concrete required for the foundation. Bill came from Thuringia - possibly, Made in Germany? I do not know, but I am satisfied so far, finally, of course, the assessment only after a hurricane possible.
Wall thickness is only about 1 mm (not much ...). The tubes I have plugged into each 1 x wrapped with remnants of the supplied thin packaging film, so they sit assembled more firmly without scratching the aluminum coating.