Genuine OEM Audi Lower Fuel Pump Retaining Ring, part number 4F0201921A. This critical component is designed to securely hold the fuel pump in its correct lower position within the fuel tank assembly. Made from durable white plastic, it measures approximately 0.19m in diameter. Using a genuine OEM retaining ring ensures a precise fit and proper sealing, which is vital for preventing fuel leaks and maintaining fuel system integrity.