Genuine OEM Audi Coolant Expansion Tank Retainer, part number 4M0121412E. This component is designed to securely hold the coolant expansion tank in its designated position, preventing vibrations and potential damage to the tank or its connections. Made from durable, molded plastic, it measures approximately 0.235m in length. Using a genuine OEM retainer ensures precise fitment and the correct mounting points, maintaining the integrity and stability of the cooling system.