Ultrasonic/Electromagnetic Pest Control/Repellers don't work. Since 2003 the FTC required the makers and marketers of these devices to provide support for their claims. They haven't. The FTC also prohibitted all the companies accused in a complain (Riddex, Jr and Plus, Pest-A-Cator, Too!, Plus and Too! Plus, PestVacator 800 and 1500, etc. from making unsubstantiated efficacy representations for any pest control device, specifically, the order prohibits any pest control product of their kind to state that it repels, controls, drives away or eliminates, temporarily or indefinitely, mice, rats, cockroaches, or any other insects or animal pests, and that it does so in any area of a certain size, or that is an efective alternative to, or eliminates the need for, chemicals, pesticides, insecticides, exterminators, or any other pest control product or services, or that will alter the electromagnetic field, send a pulsating signal, or otherwise work inside the walls of through the wiring of homes or other buildings in a manner that effectively repels, controls, drives away, or eliminates pests.