Product review (2 stars): Vent blocks with lint.
Edit: after I got my dad to remove this this for me we see that it's just some twigs. However even after we twinned some lint we could see that this would just happen again. Apparently the lint stuck because it created condensation from the heat hitting cold air. We didn't put thid cover back on.
 This vent is clogged less than a year after installing.  I'll have to get someone on a ladder to take this down and clean it out (second story).