... spring,sofa spring,seat spring,no sag spring. OKE clip knot (no sag spring parts), zigzag spring,no sag spring,sinuous spring,coil ... :18,loop height:48)(2) OKE clip knot (used with no sag spring) 1).high-tech plastic material 2).economical and ... circularable 3).obviously time-saving 4).fixed clip distances, no need mark 5).eliminating friction and noise 6).used with Zigzag ...