You do have to make sure it catches well on vent slat

I said 4 stars instead of 5 because for my fingers it's hard to grasp the knob to tighten it to the vent slats.

The only trouble I have had is securing it to the vent slat

Also, I think this would work better if my vent slats were wider - they're relatively shallow, so the clamp keeps sliding forward until that notch in the back stops it.

Too heavy for small vent slats

Bought a second for my wife!my car the vent slats don't work with it, but I glued it in so it stays works great

What'd nice as