I haven't needed to use a long zipper for a long time, but there was a time when I was in "slipcover" mode and also in the "duvet" mode and needed them. My local Joann's sold them loose as upholstery zippers and they really fit the bill. Of course, you had to know how to insert in a zipper in the seam, which I did. Nowadays, you could probably find directions online or on youtube. Since Joann's still sells upholstery fabrics, they probably still have the zippers. I think any store that sells upholstery fabrics would probably have them. Just takes a simple phone call. Good luck!