Genuine OEM Mercedes-Benz Ignition Coil Protective Hose, part number A0039978851. This protective hose connects to the ignition coil, shielding it from moisture, dirt, and other environmental contaminants. It is a crucial component for maintaining the integrity and performance of the ignition system. The part is made of flexible rubber. Genuine OEM parts ensure the correct fit and material properties for optimal protection and longevity.