The Victor PestChaser Rodent Repeller emits ultrasonic frequencies that send mice and rats scurrying. The device uses varying frequencies to prevent rodents from getting used to the noise and to keep them from returning. While the high-frequency noise is loud to rodents, it is safe for use around people and non-rodent pets when used as directed. It's also easy to use - all you have to do is plug it into a wall outlet and let the repellent do the work for you. Despite its small size, the Victor PestChaser Rodent Repeller offers mighty rodent protection. This plug-in repellent device is ideal for average-sized rooms including kitchens, bedrooms, attics, living rooms, and more. Ultrasonic frequencies can't travel through walls, so use one PestChaser per room you want to protect. The Victor PestChaser Rodent Repeller comes equipped with a built-in nightlight that emits a soft glow. The gentle illumination is not only great for navigating around obstacles at night but also lets you know the device is working. Note: Ultrasonic sound cannot penetrate furniture, cabinets, or walls. Multiple units required for multiple rooms. Rodents that are hungry or tempted by easily accessible food may find another route around your protected area, so it is best to remove all likely food sources prior to use. PestChaser works best to repel rodent populations when used with other rodent control methods as part of an integrated approach to trap, repel, and monitor infestations.