Corrugated double-wall polypropylene formwork tube with nominal diameter DN 1400, outer diameter 1583 mm, 183 mm wall thickness, in 3 m lengths with plain tube ends. Ring stiffness class SN8 in black polypropylene. Used as lost formwork for cast-in-place concrete foundations, allowing large-diameter concrete piers to be cast to consistent geometry without conventional shuttering. Typical applications include foundations for wind-turbine towers, lighting masts, and heavy industrial equipment. Country of origin: Norway.