Outdoor spiral staircase in galvanized steel, made up with 12 treads + triangular-shaped landing (only square cavity) with balustrade on landing. The height of tread is adjustable from 20,7 to 23,1 cm. Available in 3 diameters, 120 cm, 140 cm and 160 cm, you’ll may reach a maximal height of 300 cm landing level. In option : kit extra tread, landing balustrade (module 100 cm).