The window goes into the opening in the trailer wall from the outside. The "clamp ring" goes on the inside of the wall, screws go through it into a slot in the window frame to hold the window in place. On our
Uhaul, when I installed a
Scamp window I had to put the clamp ring on backwards because apparently
scamp has a thick wall whereas
Uhaul has a thin wall. Window and clamp ring have to fit together so when the screws are tightened they draw the window against the outer wall of the trailer. If Scamp sent the foam sticky tape with the
windows I strongly suggest that you not use it as it may prevent the window from drawing in tight and sealing good. Tried it on my
windows and they leaked. Pulled them back out, removed the foam tape, put them back in with the black butyl tape, no more
leaks.