LATEST DUAL CHIP TECHNOLOGY: The ultrasonic pest repeller is equipped with the latest chip to enhance the ultrasonic waves, and it constantly change the ultrasonic frequency between 25-65KHz to disturb and irritate the nervous system of pests. To make them uncomfortable and force them to leave your home and never become immune to the sound. Effectively to repel all kind of pests. Such as mice, cockroaches. SAFE & ENVIRONMENT FRIENDLY: Destroying the living environment of the pests physically, the ultrasound waves only effects on pests and mice. For child/pregnant women/The aged/pets, the pest Repeller is safe and not interfere with domestic appliances. Quiet and non-radioactive operation. Read Less