A customer in Watertown, MA called hearing scratching in the attic. Upon the inspection we found evidence of Squirrels entering through the roof vent guard. Here is the before photo of no vent guard. Here are the materials we use to install the Roof Vent Guard to exclude squirrels and other animals The finished product! Roof Vent Guards are effective and a sure way to keeping any critters out of your home! Roof Vent Guards are a great way of keeping pesky critters out of your home.