[2024 UPDATED TECHNOLOGY] Our Ultrasonic Pest Repeller's dual ultrasonic and electromagnetic chips emit ultrasonic frequencies that interfere with pests' auditory and nervous systems, causing them to feel uneasy and uncomfortable, thus keeping pests, mice, rodents and mosquitoes away from your home. EASY TO USE Simply plug the ultrasonic pest repeller into an outlet. If the repeller shows blue light and flashing, it means the best ultrasonic pest repeller is working properly. No batteries are needed, just plug in the bug repeller and use it. Be sure to mount it vertically 10-50 inches from the floor. And make sure there are no obstacles such as curtains or cabinets in front of the Ultrasonic Pest Repeller. Safe for Humans and PetsThe ultrasonic frequency of the electronic mosquito repeller is inaudible to humans and pets, environmentally friendly, the rodent repellent ultrasonic plug-in does not destroy insects but removes them from the covered area without the use of chemicals or fumes, which makes it an ideal choice for those who don't want to clean it for a long time. Effective Wide CoverageThis indoor rodent repellent ultrasonic is suitable for 1600 square feet area, widely used in homes, warehouses, offices, gardens, hotels and more. We recommend you to install one in each room as the ultrasonic waves cannot penetrate walls and solid objects. However, for areas with severe pests, we recommend installing 2 or more repellers.