This is a zig zag type spring that is commonly found in modern day sofas, armchairs and some dining chairs.
The springs are connected to the frame of the sofa or chair with a K clip.
These springs need to be fitted under tension.
The best way to to order the correct size of sinuous spring is to remove and measure an existing spring, or you can measure the internal distance from the front to back seat rails, minus one inch and that should be your size required.
These springs can come arced, semi arced or flat.
When fitting springs it is best to tie the springs together making them work as a unit instead of individually, we recommend laid cord for this and it is available under spring accessories.