Genuine OEM Volkswagen Coolant Hose, part number 5C0122101S. This hose facilitates the flow of coolant within the engine's cooling system to prevent overheating. It is positioned as part 1 in the diagram. Constructed from robust materials to ensure durability and resistance to the harsh conditions of the engine bay. Genuine OEM hoses are critical for maintaining the integrity of the cooling system, ensuring proper coolant flow and preventing costly engine damage.