I bought a Vensmile Triple Rodent Repeller, that looks just like this one. Our hope was to get rid of the squirrels or bats that took up residency inside our exterior walls, keeping the kids awake at nights. We placed it along a wall with the most activity, with no success. We knew that it might not work through a wall however. Another downside, I could only hear the click, but our kids could hear the ultrasonic sound, and my 5 year old grandson wouldn't go into the same room while it was on because of that sound. Repels grandkids? Not what I wanted!