Genuine OEM Audi Side Mirror Mounting Base, part number 8W1857409BC9B9. This component serves as the primary structural support and attachment point for the exterior rearview mirror assembly, housing the internal mechanisms. It is designed for the left side of the vehicle. Weighing 1.23 kg with dimensions of 0.285m x 0.25m x 0.18m, it is finished in Satin Black (9B9). Choosing a genuine OEM mounting base ensures exact bolt patterns, proper alignment for the mirror glass and motor, and durable construction for long-term reliability and safety.