Product review (1 stars): Worthless Garbage
My home builder unfortunately epoxied one of these to the side of my house. Within two years, all of the plastic flaps had become brittle and cracked.  Two of the flaps had broken off completely, leaving the vent completely exposed to the elements. I had to purchase another vent just to replace the flaps on the existing one. I'm sure I'll be back in another couple of years unless I finally get fed up enough to tear the whole vent out, epoxy & all