4. Filamentous yarns are preferred as warps 4. Spun yarns are used 5. Yarns are stronger 5. Weaker yarns can also be used 6. Twist is more and yarns per inch is also 6. Twist and yarns per inch is less.

A centered application is the method generally used. c. Invisible zipper: These zippers are the newest type of zipper. As the name implies, they are structured differently from other zippers and are in a special way so that they disappear into a seam. When properly applied, neither the stitching nor the zipper teeth or coil is visible on the outside of the garment. Invisible zippers are used principally in skirts and dresses but they can go, in general, wherever a conventional zipper might be used, except in a trousers.