Good, but it depends on the use. I put it on a bar on the bike and it wobbles (mainly the plastic "gears" inside) on bumps, from the vibration the bike makes from the engine. I believe the accessory that attaches to the mirror will do a better job in terms of wobbling. On my old bike I had another one from hoco that closes like a window with a membrane and magnets, it was also sealed and it was amazing. In general, very good company and very good prices!