Put one of these on a cuddy windshield and loved it so much, I tried mounting one on the windshield of my pontoon which had no mirror at all... So far, so good... clamped tight... EXCELLENT view to the rear with extremely wide angle due to convex shape. So good I have installed this mirror on all of 3 of my boats. Good merchandise, fast shipping, excellent quality and I highly recommend it. So much better than the tiny little mirrors you see normally. With this mirror, the pilot is not constantly changing the pitch of his mirror to see what's back there... GREAT!