From the Manufacturer : Whether you drive straight in or back into your garage, it can be tough to judge if you’ve stopped in the right spot. The Parking Alert guides you with flashing lights as you pull into your garage so you can be sure you stop at the desired place! No more tennis balls hanging from the ceiling. No more stopping the car, checking your position and moving the car another-Feet. This product makes parking in the garage so easy! The Parking Alert consists of two parts: the Sensor Module – Mounted on the wall at bumper height; and the Display Module – Mounted on the wall above the Sensor Module where it can be easily seen by a driver. The Sensor sends out harmless ultrasonic pulses that are bounced off objects in front of it. When a vehicle is detected, more pulses are sent out to determine vehicle speed and distance. Then the Display Module’s yellow light begins flashing slowly. The yellow light flashes faster as it tracks the vehicle. When you have reach…