Parking Sensor is a vehicle safety products. It can detect the distance of the obtacle back the car when reversing. Its main functions: 1.Adopts original microchip components imported from the USA 2.Digital display of obstacle distance 3.Alarm by growing buzzer 4.Tell of the position (left or right) of obstacle 5.Super anti electric-magnetic interference 6.The embedded four ultrasonic sensors detect automatically the distance between the rear of the car and the obstacle. 30.5cm*7cm*4.5cm