#4 is a medium weight invisible SEPARATING zipper on a mesh instead of a twill tape. This makes the zipper more flexible for use in lighter weight fabrics like satin or jersey or sport knits.
I initially purchased these for fancy horse clothes for a friend. They are now used in bicycle jerseys, evening clothes, blouses, and anywhere you need your garment to open completely, but don't want the zipper to show.
Invisible zippers are NEVER as strong as a standard coil zipper. If you have questions about your application, email or call. We are always here to help!
Installation is simple without an invisible zipper foot. Use your standard zipper foot & stitch in the ditch.