Each spring features a back bend design at both ends, ensuring the spring stays securely in place. The springs are precision machine-cut for accurate and consistent sizing, with clean cuts, no burrs, and resistance to rust. This sofa spring repair kit is designed to attach zigzag-shaped, non-recessed springs to the wooden frame of upholstered furniture for use in seat or back support. Made from carbon steel and heat-treated for enhanced elasticity and durability, the springs offer reliable performance. The design includes a 48mm high arch and 25mm short spacing, providing strong support with reinforced material feet. Restore sagging cushions and extend the life of your furniture with this repair kit, which includes all necessary components for rebuilding a chair or repairing a worn sofa frame. A cost-effective solution for restoring comfort and support without replacing entire pieces of furniture. These springs are the same type used in commercial and custom furniture manufacturing.