Slide seals are available from any RV parts dealer, in Montana's case Trekwood.com. http://www.trekwood.com/parts-search...23+%2F+Keyword
But since I just had the seals replaced on the outer edges of all my slides, don't expect it to be cheap. I my case the stuff was sold by the roll to a dealer near where I was in Florida. I paid to have it done because the toppers had to be removed and replaced and with a Knee replacement coming up I didn't have either the physical ability to work on ladders that long, nor a friend to help me with the toppers.
Dick, Joyce, Diego, Picatso and Gustav
2017 3720 RL, and 2013 HC 343RL
2017 3500 Dodge Maxi DRW 4X4, Pullrite Hitch, IS, Disk Brakes, 3rd AC, Winegard Traveler, Bathroom door mod, Dometic 320, couch for desk swap, etc.