Coil Zippers use the toothed elements of helical coils of polyester as the fastening system.
The opposing elements of the exposed coil interlock with each other to form the closure. The coils can be formed and woven directly into the supporting tapes or preformed and sewn onto specially pre-manufactured tapes in a separate operation.
These products are widely used because of their inconspicuous appearance when incorporated into the finished product and their ability to mould around corners without buckling out (as in the case of moulded zipping). The coils will generally not break an industrial sewing machine needle if stitched over, which allows bar tacking as a method to close one end of the zip.