Genuine OEM Volkswagen Engine Expansion Reservoir Retainer, part number 4M0121214A. This component is designed to securely hold the engine coolant expansion reservoir in its correct position, preventing vibration and potential damage to the cooling system. It is located in the engine bay, supporting the expansion tank. Weighing 0.1586 kg, this retainer provides robust support. Using a genuine OEM retainer ensures precise fitment and the necessary strength to maintain the integrity of the cooling system under various operating conditions.