Genuine OEM Audi Fuel Filler Neck Insert, part number 8T0809906B. This component is designed to fit within the fuel tank assembly, specifically at the fuel filler neck, providing a secure housing and sealing surface for the fuel cap. It plays a critical role in preventing fuel evaporation and contamination. Weighing 0.481 kg and measuring 0.275 meters in length, this genuine OEM insert ensures a precise fit and material compatibility with fuel, preventing leaks and maintaining the integrity of the fuel system.