Genuine OEM Audi Intercooler Return Air Line, part number 3C0145770E. This air line is responsible for carrying cooled, pressurized air from the intercooler back to the engine's intake system. Weighing 0.473 kg, its rigid construction and precise routing ensure efficient airflow and resistance to pressure fluctuations. Using a genuine OEM air line guarantees correct fitment and sealing, preventing boost leaks and maintaining optimal engine power and efficiency.