finished: black painting
square tube
sinuous spring
sofa seat box
metal seat box

It always used for sofa seat and chairs. We use clips to connect the spring and matal frame. We can use two types of sinuous spring to make the metal seat box. one is normal zig zag spring.  another one is abnormal.

with many years experience, we can finished it with high quality. it is always popularity in America market.

metal seat box