[2023 UPDATED TECHNOLOGY]: The dual ultrasonic and electromagnetic chips of our ultrasonic anti-parasite repellents emit ultrasonic frequencies that disrupt the hearing and nervous system of the parasite, making it comfortable and uncomfortable so that parasites, mice, rodents and mosquitoes from home Easy to use: just plug the ultrasonic repels into the socket. If the pest control agent shows blue light and flashes, it means that the best ultrasonic control agent is working normally. battery required, just connect repellents and. Be sure to install 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 control agent [SAFETY FOR PEOPLE AND ANIMALS]: The ultrasonic frequency of the electronic mosquito repellent is inaudible to humans and pets, environmentally friendly. Ultrasonic rodent plug does not eliminate insects, but eliminate them from the covered area, use chemicals or smoke, which is a choice for anyone who does not want to clean for a long time [EFFECTIVE COVERING] This indoor anti-rodent ultrasonic is suitable for an area of 1600 square meters. It is widely used in homes, warehouses, offices, gardens, hotels, etc. We recommend installing one for each room as ultrasonic cannot penetrate walls and solid objects. However, for areas with severe pest we suggest install 2 or more pest control agents