Horizontal Rotary Hook. Good quality ready to wear garments will often have an invisible zipper fitted. These zippers are often neglected by the home dressmaker which is a pity because they can ensure success everytime. Invisible zips are suitable for all fabrics from fine silk jersey through to suite weight wools and tweeds. The key is to get the needle as close the fastener as possible, which this foot accomplishes by slightly unrolling the zipper just before the needle. once fitted, a well sewn invisible zipper will merely look like part of the seam. This foot makes it easy to insert an invisible zipper.