"...We have it for our 5th wheel..."

We use it on ours too, mainly for that huge picture window on the rear end, and the clear dome over the shower (which makes it really bright in the mornings when we want to sleep in). I replaced some of the window frame screws with the screw-in male parts of snaps, then installed the female snaps on the foil to hold it in place. Looks kinda hokey from the outside, but really helps on the inside...