Genuine OEM Audi Expansion Tank Reservoir Hose, part number 8K0121081T. This hose is a vital component in the engine cooling system, connecting the expansion tank to the main cooling circuit. It ensures proper coolant circulation and pressure regulation. Weighing 0.059 kg and measuring 0.42m in length, it is designed for precise routing and durability. Using a genuine OEM hose guarantees the correct material composition, resistance to heat and pressure, and exact fitment for reliable cooling system operation.