Working principle: This ultrasonic insect repellent is equipped with an intelligent microelectronic chip, a specially designed wave ultrasonic wave (12-24KHz) and a LED flash. Effectively stimulate and destroy the brain and auditory system of rats and other pests in the control area, making them feel scared and uneasy. Then quickly run away from the scene. 3 in 1 power supply method: Compatible with DC cable, USB cable and 4 AA batteries (not included). You can connect two wires to the car circuit. The car will automatically shut down when it starts to save electricity, and automatically resume work after stopping. Although this rodent repellent is designed for vehicles, it can also be used almost anywhere, such as warehouses. High Quality Mouse Repellent: ABS material, high temperature and fire resistance, will not affect other auto parts or engines. You can add insect repellent powder (not included) to the mouth of the powder to increase the effect of insect repellent and rodent control. The screw-on lid prevents accidental leaks. Safely repel pests: This ultrasonic mouse repeller uses physical methods (combination of ultrasound and flashing LED light) to destroy rodents and insects, such as mice, minks, cats, cockroaches and spiders. Completely ecological. Moreover, it is safe and harmless for adults and children. Special Note: The effect may not be obvious after a few days of use, but the effect will be evident after 3-4 weeks of continuous use. There may be more active mice at first. do not worry. This is because rodent repellents can irritate mice. Over time, the rats became less and less numerous until they disappeared completely.