Product review (3 stars): it does what it's supposed to do but after a ...
it does what it's supposed to do but after a year of so my flaps were warped (maybe from the sun?) and they are now sticking open.  I took it off and cleaned everything put it back on and a few weeks later they were stuck open again.  it's 10 degrees outside right now so my dryer is ice cold when you open it.  I ended up pulling it out and replacing with an all metal vent.  Lets see if this one holds up.