A kind of economic spiral staircase. Steps are manufactured by  beech plywood. Contains no handrail. Barriers and main conveyors colored with electrostatics powder point upon iron. Step widths, 60, 65, 70, 75, 80 cm. In other words, 120, 130, 140, 150, 160cm diameter.
 
Heights between  280 - 300 cm. For montage, stairwell in the shape of square or circle stairwell needed. Top of the ladder  is to be fully open. Montage can be perform by metal or wooden works constructor.