Product review (5 stars): Destroyed by icicle
The construction quality of this unit is terrible!  As you can see in the photograph, it completely fell apart when a large icicle fell on it.

I'm kidding, of course.  It really did get whacked by an icicle, but before that it worked perfectly.  This is a great product--the only dryer vent that actually blocks cold air, backdrafts, and unwanted creatures.  I did buy a replacement and wholeheartedly recommend it to others.