Cushion for dinette zipper broken

[onetonford]

Broken slide on zipper I tried to find a repair kit for zipper cannot find the correct size. As near as I can see a number on the bottom of slide is a #4 but all I can seem to find are #3 or #5 no #4 is this special to forest river or what? has anybody had to replace the entire zipper and were can I find them without buying yards of zipper material and slides etc. was looking for easy fix with out spending $$$$$

[cavie]

upholstery shop.