I got two cats, Thelma and Louise and their room has a big sliding glass door. We also have racoons that come around and my kitties can see them through the door. I usually cover it at night but sometimes I forget and if the racoons show up both of my kitties commence to marking their territory. This machine is absolutely perfect for the job it's needed for. And for right around a hundred bucks too. Works exactly as advertised. Great solid product.