Product review (5 stars): Effective, easy to use vent guard
let me start off by saying that this is quite simply a very effective and easy to install tool! Its simply a thin sheet of plastic that has been perforated to allow air to flow through. It took me less than 5 minutes to install them into 2 different vents (1 dryer, 1 bathroom fan). Be sure to watch the 40 second youtube video for installation instructions. Like the picture shows it actually sits right behind the louvers, it is not in the vent piping, to install you actually remove the top 2 louvers and simply slide it in the slot between the louver and the housing. I had to remove 3. I couldn't be happier with it, the sparrows that were setting up shop in my dryer vent have been stopped!!!

If you have a smaller vent simply use a pair of shears, or a knife to cut the mesh to the proper size.

It's a great product, I highly recommend it!