I fitted these to my motorhome to help with leveling - one on the bow and one under the vault door walkway. I would give five stars because they work well and are very useful, but after the third (very short) ride with them on an RV the nose block was missing all of the bubble glass. It just disappeared! Too bad - it's a little expensive to just hop off. I wouldn't expect that. Maybe the wind has picked up? I'm curious if the seller will offer a replacement. I'll send a message and see what happens.