Square profile pipes GK ALYuMINIEVAYa TRUBA 1955, A5, AD1, AMg1, AMc, D1, etc.

A square aluminum pipe is an aluminum profile with one or more hollow spaces inside, the length of which can reach six meters, so that the possibilities of pipe operation are significantly expanded. A special coating (most often anodizing, sometimes powder coating), to which almost all products of this type are subjected, protects the metal from oxidation, which increases the long–term use.
Square aluminum pipes bend perfectly, and because of their flat faces they lend themselves well to bonding. They are convenient to use for air ducts and cable laying, they are easily mounted into the wall or floor, and look aesthetically pleasing enough not to spoil the interior design.

Brands: 1955, A5, AB, AD, AD1, AD31, AMg0.7, AMg1, AMc, AMcC, D1.
GOST 18475-82.