Thanksgiving 2007 we found ourselves literally overrun by mice - it was real shock to us - we tried several different kinds of snap traps which never worked. We then resorted to live capture traps which worked very well but left us with live mice (and it didn't feel very sporting to kill them once I'd caught them). So we went out and bought the plug in ultrasonic deterrents and they work perfectly! The package says it'll take several days to get rid of the mice, but we didn't see anymore mice the moment we plugged these in - you can get them at Lowe's or Home Depot or probably anyplace. Ours were made by Victor and cost $20 for three units.