The one I got emits some kind of ? -- laser, maybe ? -- I got it at the grocery store and it was close to 20.00. I think the TV one emits some kind of vibration throughout the walls. I've never had one of those, so I don't know whether they work or not.
I had seen a mouse in my bedroom!! So I plugged one in in there and I haven't seen or heard him since. No signs either. The only thing--you have to have one for each room because the laser or whatever won't go through walls. I will probably one at a time until all rooms are covered.
They must work then. You bought it in a grocery store? What is the name of the device? Maybe I can find some of those around here.
The ones I've seen at Walgreens, etc. is the kind that supposedly goes through the wires of the house. They said you need to have one for each floor. I technically have three floors - the main floor, and upstairs and a basement. I suppose I would have to put on on each floor, including the basement, otherwise the mise would simply run down there and then Cory would be infested with mice! He wouldn't like that!