From a circa 1994 Cole Sewell Storm door its a retainer strips
it holds the window in place in full storm door...it is essentially plastic. Made to pull out and put in full screen in summer
Any similar will likely do Need for top and 2 sides or cut to fit like 15 ft worth
We do not sell this type of retainer, unfortunately. The problem with these kind of strips is that every manufacturer has their own idea of how they should be designed, and then they change their mind every couple years to boot. It makes it hard for companies like us to keep up.
My first recommendation to you would be to take the undamaged lengths of strip you have now and cut it into equal portions, maybe a couple inches long. You can then distribute them evenly around the frame. The secret to these things is that you don't actually need the whole strip for it to function. We used to just use tiny retainer clips for storm doors back in the day, and it still works great for newer doors like this.
If that doesn't work, let me know and we can come up with something better.