Genuine OEM Audi Coolant Hose, part number 03L121157AQ. This flexible rubber hose is an essential part of the engine cooling system, responsible for transporting coolant between engine components and the radiator. It features a specific curved shape for precise routing and connection, measuring approximately 0.305 meters in length. Using a genuine OEM coolant hose ensures the correct material properties for heat and pressure resistance, preventing leaks and maintaining the integrity of the cooling system for optimal engine performance.