The dual frequency conversion technology uses dual ultrasonic and electromagnetic chips to confuse the hearing and nervous systems of the pests, disturb their bodies, make them feel uncomfortable, and flee the place to achieve the goal of repelling all mosquitoes. Not only are they effective at repelling mice, cockroaches, mosquitoes, spiders, ants and other pests. Ultrasound against pests is effective in indoor spaces up to 80-120 square meters and has a wide range of applications. In homes, warehouses, offices and hotels. Since ultrasonic waves cannot penetrate walls and solid objects, it is recommended to place the device in the room. For dense or large areas, additional units are required. Extensive use of electronic repellents will keep you safe from all pests at all times. i.e. spiders, mice, mosquitoes, cockroaches, ants, snakes, butterflies, wasps, moths, fleas, flies, etc. Never immediate results; but you can see a difference after 3 to 5 minutes with 4 weeks of use. Easy to use, the electronic repeller will turn on when plugged into a power outlet. Repel pests by emitting blue light. It is recommended that the plug be installed 30 and 50 inches from the ground for flying pests and 10 and 30 inches from the ground for crawling pests. Insects use ultrasonic frequency, which can replace sprayers and traps, no odor, no dead bodies, 100% safe and harmless to humans and pets. Get rid of flying and crawling insects with painless treatment. No chemicals, non-toxic, low power consumption.