Ultrasonic Repellent - This is our advanced version. Using ultrasonic theory, change frequency to stimulate the auditory system of mosquito and other pests, make them unbearable and feel uncomfortable. Wide Coverage Area - Each ultrasonic electronic pest repellent is effective for a large area up to 800-1300ft². Please note that ultrasonic waves cannot pass through walls. Although our pest repellent works well, if you have a large infestation, we recommend placing our insect repellent in each room. Easy to use - This machine should be installed 80-120 centimeters from the ground. And vertical to the floor and plug into the power outlet. It can be plugged directly into AC 110V power outlet (power range: AC 90V-250V Frequency: 50-60HZ). Commonly used in homes, warehouses, stores, hotels, hospitals, offices, etc. Large areas may require more than one unit. Environmental and safety friendly - The product is non-toxic and environmentally friendly, our repeller is 100% safe and