Used the standard film version - not "cling". Laid the strip on the exterior surface to mark up for trimming. My wife shone a flashlight through from the inside so I could exactly follow the interior edge. Marked up with magic marker, trimmed with sharp scissors. Found the spray solution essential. Removed entirely from the backing and with both the film and windshield wet with solution it was super easy to slide into place. Just a few strokes with a small bathroom squeegee and it looks like a professional installation.