This professional ultrasonic rodents repeller adopts frequency conversion output technology, which emits a combination of fluctuating ultrasonic waves and strobe lights to deter pesky animals entering your automobile, RV, Trucks, so that can greatly reduce the hearing resistance of rodents, and the repelling effect is amazing. Once installed, it will last a lifetime. (NOTE: This rodent repeller is not suitable for vehicles with voltage over 24V.).This rodent repeller for car has power-on self-test and vibration detection functions. The 12v model turns off when it senses movement and has a safety shut off to not kill your battery. The working mode is automatically turned on after 5 minutes of vehicle parked to keep the car free from pests such as mice, squirrels and rodents etc, but does not bother pets. Easy to install with zip ties long enough to place the device in suitable spot..Rodents are really scared of fluctuating ultrasonic waves, glare and flashing bright light from this pest repeller in the dark. The white strobe lights flashing in the car will have a more frightening effect on the Mouse, chipmunks, critter, rodents etc. which is much better solution than constantly setting up rodent traps or poisoning them..This under hood rodent repeller uses 12V conventional car battery power supply, no need to use another power supply, easy to install and use. Reverse connection protection function prevents artificial connection of reverse circuit and damage to the product..Designed for vehicles but can be utilized almost everywhere such as garage, warehouse, attic, barn, shed, basement, farm life etc. where a 12 or above volts battery is available.