Product review (3 stars): Not a Quality Vent Product
This was the same model that was installed on my house, which needed to be replaced since the plastic was crumbling from ultraviolet exposure.  It took me some time to totally remove the old vent...piece by piece with plyers, screw driver, etc., but was able to fully remove the old plastic parts.  This new vent was able to fit, and I used silicone caulking to secure it in place (I recommend silicon, since it is durable and extra amounts don't show up as much as inferior caulking).  The only problem with this new vent is that the flaps don't fully open and close when the dryer comes on.  I have silicon spray to try and make them move easier, but the flaps still aren't opening and closing smoothly.  Not such a good product...next step will be to totally remove the flaps and try to gently sand the stubs that fit into the sides, and hopefully that will allow the flaps to open and close like they are supposed to do.