These things are terrible! they vibrate so badly that all they really do is act as an "early warning" of whether or not there is a blurry shape in the lane that may or may not be next to you. They are seriously useless. Add to that, the fact that they make a shrill whistle at anything over 20mph . . . I drive an hour to work, and I couldn't take it . . . took them off as soon as I got to work. Just terrible. They serve the purpose of having mirrors if legally required, but that's about it.
Price: $30.00 Pros: Cheap legal mirrors Cons: Vibration,will not stay in position. Recommended? No
Comments: Can't tell whether it's a Smart car or a semi behind you due to the vibration. Over about 20 mph and they blow out of adjustment. I had to Super Glue mine into position.
They are cheap legal mirrors, that's about the extent of them.