Genuine OEM Volkswagen Coolant Hose Assembly, part number 4M0265356K. This assembly connects the auxiliary heater to the engine's cooling system, allowing for pre-heating. It is positioned as part 1 in the diagram. The hose is constructed from durable rubber designed to withstand high temperatures and pressures. Genuine OEM coolant hoses ensure precise routing and material integrity, preventing leaks and maintaining the cooling system's efficiency.