Product review (4 stars): It works.
We were desperate for a "fix" for birds that seemed to insist on nesting in our dryer vent. Our laundry is on the second floor and we found that a lot of traditional products that are sold were not going to be an easy install for one reason or another. We thought of putting metal netting inside, but a laundry repair person cautioned me against using a screen that was too fine or it would trap stray lint and become a fire hazard.

We purchased this product on a whim after being awoken by birds in the vent - again - at about 5 am. I think I ordered it from my phone in my bed without doing too much research. I'm pleased to say it works GREAT, but I will forewarn you that we were a little nervous after receiving it. The packaging was a Ziploc sandwich bag with a computer-printed label stapled to the top. Looked a bit homemade but, you know what? It works.