Vertical weather strip on 1994 Weathershield sliding patio door

Thanks for reaching out to us. I'm afraid we aren't able to identify your weatherstripping from these photos. We would need you to remove an undamaged sample and show us a photo of the end profile. Yours appears to be very brittle so I'm not sure if that would be possible but that's the only way for us to help, unfortunately. 

Yes, thank you! We don't sell the insert strip shown here. The only thing we may be able to help with is the pile weatherstripping depending on the dimensions and if it can be removed. We would just need you to write out the base width and pile height to help narrow down some options.