Despite the incredible technological advances, the best quality sofas can still only be made by hand using traditional technology. Using a taped and glued wooden frame, iron wave springs and a load-bearing iron base. Wave springs (flat steel strands stretched between the wooden frame under the seat) not only provide the flexibility and support that is important for the spine, but also distribute the maximum load on the seat. In this way, the fabric and padding do not start to sag or stretch at the points of greatest stress. It's an expensive technology, but furniture made this way will stay comfortable and looking new for decades, and a sofa made this way will last a lifetime.