Genuine OEM Audi suspension air bellows, part number 4E0616137. This protective sleeve is designed to shield the air suspension strut assembly from dirt, moisture, and road debris, preventing premature wear of the internal seals. It is located on the air suspension strut as shown in the diagram. Genuine OEM bellows are manufactured from high-grade, flexible rubber compounds that maintain their integrity across a wide range of temperatures, ensuring the longevity of the air suspension system.