Advanced technology and long-lasting effect This ultrasonic repellent bombards the nervous system of most types of flying and crawling insects. Effectively bombards mosquitoes, spiders, bedbugs, cockroaches, mice, fleas, etc. No chemicals and eco-friendly No chemicals or noise. The sound is not recognized by the ear and therefore does not disturb or stimulate humans, cats or dogs. Our ultrasonic repeller is safe for your families and pets. Won't harm your living environment. Ultimate indoor coverage - Our mouse repellent kit contains 4 small but very powerful units. Each ultrasonic rodent repellent is small and quiet and covers up to 1700 square feet to protect your home, furniture, pets and family all year round. It is widely used in homes, warehouses, offices, gardens, hotels, etc. Easy to use: just plug the ultrasonic pest repellent into a power outlet. Install our item at a distance of 7 to 16 inches from the ground. Quantity delivered: 2 pieces