I'm looking to sew a pair of Winter shell pants and want to use waterproof zippers instead of using flaps. The tricky part is finding the right zipper for the side zips. They must be one-way separating with 2 sliders but I cant seem to find them at the usual outdoor on-line fabric shops. Any ideas where to find them?

Basically like all shell pants the top zipper can be opened for ventallation and the bottom zippers pulls up so you can get them on over boots. a la Patagonia, mtn hardware, arc-teryx.
Thanks

I have not seen exactly what you are asking for but unless you really need to be able to completely separate each side you can get what you are looking for using continuous coil uretek zipper stock with 2 slides installed with the "closed" ends facing each other.

Thru-hiker sells this in #3 size. There are other sources that stock #5