Ultrasonic protection for out of reach areas. Anti Mouse Mini-Sonic® Mouse Repellents from The Big Cheese® are a discreet and effective way to drive rodent pests out of homes and living areas. The welfare-friendly, plug-in deterrents produce ultrasonic sound waves that are inaudible to humans and non-rodent pets, including cats and dogs, but are within the hearing range of mice and rats. Each Mini-Sonic unit will provide continuous protection of a single room. For large or irregular shaped rooms, more than one unit may be required.