First you need to know how long the zipper needs to be (the opening). If you are going to wear this you don't need a heavy duty zipper, however if it is going to be a pillow, purse, I would suggest that you use a heavy duty zipper. Most of the zippers have sewing instructions on the inside of the package. I like using scotch tape to hold the tape in place before I start sewing it in. Hope this helps you. Vickie
