The part in detail:

Part B67823816 , A-Class Rear Parking Sensors

Type:A-Class Rear Parking Sensors

Rear parking sensor kit for the A-Class (169). The distance between vehicle and obstacle can be calculated with the aid of ultrasound signals that are reflected on an obstacle. Sender and recipient of the signals are ultrasound sensors located in the bumpers. A Visual warning is integrated into the inside roof lining that can be viewed when looking through the rear view mirror, each visual warning consists of 6 yellow and 2 red light diodes (LEDs), which switch on as the distance decreases. Surveillance area at the back: 20 to 120 cm (middle area) resp. 20 to 80 cm (corner area). The ready status of the system is activated below a driving speed of 16 km/h and engaged reverse gear (or selected lever control "N" with automatic gears). Fitting is recommended to be performed by a Mercedes-Benz dealer.

Price: £202.10