Rich Package: you will be provided with 12 pieces of indoor ultrasonic insect and pest repellers, adequate in daily use, which can emit a frequency too high for humans; These sound waves are designed to distract, harass and deter common household pests such as cockroaches, spiders, mosquitoes, ants and so on, with an intelligent, multi frequent ultrasonic conversion system to let pests nowhere to hide Safe to Use: ultrasonic mosquito repellent can offer nice protection to your family in a healthy and peaceful way, you do not need to worry about the security of pets, children or pregnant women; Though cats and dogs can hear the sound of ocean waves, they cannot hear ultrasonic waves 360° Protecting Your Home: ultrasonic pest repellent can effectively cover up to nearly 1600 square feet; Because ultrasonic waves cannot penetrate walls and solid objects, it is recommended for every room; You can put them to homes, warehouses, offices, granaries, restaurants, markets, hospitals and so on Easy to Use: you just plug the ultrasonic mouse repellent into the electrical outlet, when the blue night light comes on, it will start to repel the pests; Remember to place the repeller to the place where its noise will not be affected by walls and furniture; It is recommended to mount this repeller 30-50 inches above the ground for flying pests and 10-30 inches above the ground for crawling pests Keep Home Clean: mouse repellent ultrasonic plug in takes 1-2 weeks to see the effect, mainly depends on the severity of the infestation; Besides, it is quiet while working, so it will influence on your normal life and work; Meanwhile, it avoids the trouble of cleaning dead mosquito