Genuine OEM Audi Fuel Tank Cap, part number 7E0201550C. This essential component provides a secure seal for the fuel tank opening, preventing fuel evaporation, protecting against contamination, and maintaining proper fuel system pressure. It is located on the fuel tank filler neck. Weighing approximately 0.075 kg, a genuine OEM fuel tank cap ensures a perfect seal and proper function of the vehicle's evaporative emissions system, which is critical for environmental compliance and fuel efficiency.