【ULTRASONIC TECHNOLOGY】This ultrasonic pest repeller is the 2019 version and uses a more powerful upgraded chip which makes pests and rodents more difficult to immunize than before. Produce good injuring effects on mouse, cockroach, spider, mosquitoes, insect, rat, rodent, flies, ant, fleas and more pests. 【NO HARM TO HUMAN & PETS】Based on physical pests repellent principle, this product is no harmful to human or pets. This pest repellent is safe for human and our lovely pets like dogs and cats. Not adopt the way of killing or torturing pests like roach baits, mouse glue traps, bedbug and flea foggers. Not need to clean up corpses leaving behind and have low power consumption, definitely being an eco-friendly pest repeller. 【100% REFUND & 90 DAYS GUARANTEE】Ultrasonic Pest Control Repeller is backed by our 90 days guarantee because we want to help you get rid of those pests. Typical effects can take 3-4 weeks depending on the amount of infestation. We give a 100% refund guarantee if you don't see effects after 4 weeks. 【LARGE COVERAGE AREA】The Ultrasonic Pest Repellent is effective for an area up to 800~1200 Square Feet. Please note that ultrasonic waves cannot travel through walls. It is best to use at least 1 device for each room, and use at least a couple units for areas where pests problems are serious. 【EASY TO USE】Plug in a regular power outlet, and then blue light is on. This time the machine began to work, and watch the pests go away! Please install our items to the socket about 20~30cm away from the floor.