Tom, Proflex tube says it is a tripolymer sealant, paintable, and don't use it on EPDM or styrofoam. Jack; here's a bit of info I learned the hard way. I bought a side window and a rear window from Scamp
. They came with a peel & stick foam gasket and use an inside trim ring. I was able to install the rear window in our Uhaul by enlarging the opening, and the side window by making an aluminum adapter. They both leaked, and I could not get the outside flange tight against the trailer wall. Had to pull them both out and reinstall with the butyl tape, no more leaks
. I don't know how Scamp
installs them at the factory, but that foam gasket just didn't work for me. A couple others have used the Scamp
rear window in their Uhauls, and I stressed to them to not used the foam gasket.