The best thing about the electronic devices is that you provide income for the people who build them, I bought them from Home Depot, brand says, made in China for Weitech, Inc. Sisters, Oregon..paid $30 for 2 and put them right above the drawer, less than 1 foot, the mice like to invade, Not a bit of difference, the mice still invaded, I now use the steel live traps that several mice can get in, have caught 3 at a time twice. The bad part about poison is that they may crawl into a wall and die, and can be very stinkyThey are all but impossible to keep out. We get the country mice, the big eyed, brown furred ones, almost too cute to kill, so I just toss them out and let the Jack Russel have some fun..