Its called "Trim-Lok", which is a brand, but it seems to have turned into a generic name just like "Kleenex" has for all snot rags.
I redid my 13ft Burro
. I purchased mine thru an auto upholstery place and have seen it retail in various auto/rv/boat supply stores. Its inexpensive and if you want it right away, you can just go buy it rather than wait AND pay shipping charges. Take some of the old stuff with you to get an exact size and fit.
On mine, the edges of the seam were very un even and I had to trim some of the excess flange down to get it to fit easily. Not much, but it sure helped with the "Buldge" in some areas. Apply it "Backwards"..put the open side of the trim away from you and roll it towards you, like you would with plastic wire loom. Seat it as you go.
I used a small light
hammer to get it to seat from the top of the seam. I recall I got bout 30 feet and had some left over. Its so inexpensive that it was not a loss.