4-Pack: Ultrasonic Pest RepellerThis ultrasonic pest repellent has powerful and safe technology works around the clock to protect against pests and rodents protects well in rooms of up to 500 feet! Features: This Ultrasonic pest control repeller repels pests and mice with ultrasonic waves by attacking their nervous system, which makes them even mice extremely uncomfortable. Works great for mice, mosquitoes, ants, rats, cockroaches, spiders, bugs, rodents, etc. Ultrasound through the