Not sure exactly which felt seal the Uhaul
used. However if you don't get a link then you need the following information to find a replacement.
Width and depth of the track it fits into
thickness of the window glass
of course you need to know how many feet of it you need
and you need the right keywords....
"glass run channel" You can add the word "felted" to that keyword search but nowadays there are also all silicone versions of that seal which I suspect is the better way to go versus the older felted styles that let water into the channel since they don't seal as tightly against the glass due to their fuzzy nature.