I attached this to the windshield of my boat, twisted it every way possible, slid it around to different spots, removed and replaced it, attached it to the side/vent windows, and it held up like a champ.  The mirror is wide angle and easily shows the whole transom of my 7'+ beam boat.  Most lakes in Colorado require an observer, but I love having a rear view mirror in the boat...and this one does the job perfectly.