Product review (1 stars): Poor material, but good idea
Didn't hold up to Colorado UV. Fell apart in about 2 years.. I took the ball out and went to my local duct shop and had them make me a similar uni out of galvanizes sheet stock. Added the plastic ball and been good to go for the last three years. The ball blows up when the dryer is on and fall sealing the vent when off. Plus, all lint blows away as there is no screen filter to plug up.