Product review (3 stars): Not a bad vent cover
Simple solution to help draw the air from a vent under a couch, bed or any elevated furniture blocking a vent.  The clip didn't stay secured to the vent causing it to constantly move.  My quick fix was taping the cover to the vent with some extra tape to seal against the floor.  It's not the best solution but since the vent and the vent cover are under a bed, it works well.