Intelligent Frequency ConversionThe ultrasonic pest repeller adopts automatic frequency conversion ultrasonic technology to emit 20~55KHZ ultrasonic waves, to stimulate the auditory and nervous systems of mosquitoes, cockroaches, mice, insects mites and other pests to keep pests away from your home effectively. Insect repellent safe for humans and pets The mouse repellent ultrasonic frequency is 20 ~55KHZ, and the human ear cannot hear the frequency above 20KHZ. As long as the repellent is not placed in the hearing-sensitive area of cats and dogs, it will not cause any harm to your pet. Wide Coverage Insect RepellerThis repellent rodent control can effectively prevent indoor area up to 80-120 square meters of pests, can be widely used in homes, warehouses, offices, supermarkets, hotels, etc. But for areas with serious vermin, we suggest installing 2 or more. Plug-and-Play Rat RepellerJust plug in our pest repeller, it works when you notice the misty glow. This rat repeller should be installed 10-30 inches from the ground and no other obstacles within 1 meter. They are not effective for other rooms if you install devices in one room. What You Get4 Packs of Ultrasonic Pest Repeller. No need to clean up dead pests, no bad smell and corpses, no battery required and save a lot of money.