Weatherstrip for Aluminum Sliding Window

Thanks for posting. I'm afraid I can't say what weatherstripping might work for you from this photo alone. Could you remove a sample and show us its 'end profile'? Any dimensions of that cross-section view would also be useful. In the time being, you can view our selection of weatherstripping here.

Unfortunately I can't. Without seeing the weatherstripping's end profile, I really can't say what you need. I know it's difficult, but if you can either slide out just a bit of the weatherstripping by hand, or with pliers, that would be a huge help. You can consider using a razor knife to carefully cut a slight opening on the groove where the weatherseal sits. You just want to cut just enough, so you don't damage the window, but with that you should be able slide out the wool pile.