Genuine OEM Audi Ventilation Hose, part number 4F0121107CB. This hose is part of the engine cooling system, facilitating the flow of coolant. It is positioned within the engine bay, connecting various components. Constructed from durable rubber, it is designed to withstand engine temperatures and pressures. Genuine OEM parts are essential for cooling systems to maintain precise flow rates and prevent leaks, ensuring optimal engine temperature regulation.