Description: Why choose the Ultrasonic Pest Repellent for Vehicles? Rodents and other animals might take shelter under the hood of your engine, especially during chilly winter and spring days since car engines are usually warm, dry, and undisturbed, providing an ideal shelter for feeding, resting, or breeding. Once in there, engine wires are particularly vulnerable to rodent damage. If rodents chew away the wires' insulation, it can cause short circuits, resulting in expensive damage to the engine. What's the working principle of the rodent repeller? The continuous and intermittent changing ultrasonic frequency and the high-frequency flashing of the LED light stimulate the rodent's brain nervous system, auditory and visual systems, making them intolerable and fleeing, thereby driving the rodents away from your home and vehicles. How does the ultrasonic pest repeller works? After turning on the machine, the machine enters the self-check program 1. The white and red light will stay on for 2 seconds and then enter the operating mode. 2. At the same time, the horn will continue to sound(110dB) for 2 seconds and then enter the active mode. 3. If there is a shock effect, it will pause for 2 minutes after the shock and automatically start.