The little unit sends electromagnetic signals through the wiring of the house and drives out the little field mice who like using our home for their winter nesting ground. The only technical thing you need to know concerns a rotating switch on the front of the device. We're supposed to change the selector from "random" to "continuous" once a week. And the literature says to change the pulse daily if infestation is persistent. We have a mouse motorway entrance under our ground floor toilet where the main water supply enters our home. I clean droppings from that area frequently. But after three days with the electronic pest control switched on, all the droppings have gone away. I'm a happy camper and I'm now considering extending the power cables I have in the garage since and installing an outside socket near the point where our main water enters the house.