Durability: Made from high-carbon, hardened steel, they are resilient and resistant to sagging over time.

Flexible Support: The sinusoidal design allows the spring to flex under weight and return to its original shape, providing comfortable, responsive seating.

Easy Installation: They are typically attached to the sofa frame using specialized clips (zigzag spring clips) and a clip-fastening tool, making assembly faster than tying individual coils.

Cost-Effective: Their simple design and efficient installation process make them a very economical choice for mass production, hence the "factory price."

Space-Saving: They provide a low-profile support system, allowing for sleek sofa designs without a bulky spring unit.

Customization: They can be customized in wire thickness (gauge), height, length, and number of bends to suit specific sofa designs and weight requirements.