This parking sensor system with display is the perfect accessory for parking with a large vehicle or for the frequent parallel parker -- any place where parking is tight. It includes 4 sensors, the central “brain” unit, and a display. Hooked up altogether, this is a truly ingenious system perfect for letting you know how close you are to obstacles, walls, or other vehicles. The 7-stage LED indicator shows how close you are to objects, from 0.3 to 2.0m. It can be set up to activate when you put your car in reverse. Requires 12 V from your vehicle’s battery.