Mercedes S 2010 Automatic Gasoline mileage: 150 KM This part is an original OEM Audio Amplifier / Sound System Control Module for Mercedes W221 S500 cars. It is used to control the audio system and distribute sound to the speakers inside the car, especially in cars equipped with a luxury sound system such as Harman Kardon 2005-2010. First owner, amplifier was broken, I repaired it.