A twin-wire section with a first and a second endless wire, for forming a fiber material web of a fiber suspension, notably for forming a ply of a multiply paper or cardboard web, the ply being merged on a third wire with a further ply. In the twin-wire zone formed by the first and second wires, a dewatering box (touching the one wire) that features rigid slats is contained in the loop of the one wire, while in the loop of the other wire there are contained several backing slats which can be pushed flexibly on the other wire, while a loop of one of the two wires contains a forming roll which together with said wire forms a looping zone. The forming roll has a smooth, continuous roll shell. The wire which in the looping zone is outside separates from the web and the inner wire at a distance before the end of the looping zone.