Genuine OEM Audi Belt Tensioner, part number 06B109477. This critical component maintains the correct tension on the engine's accessory drive belt, ensuring reliable operation of components like the alternator, power steering pump, and air conditioning compressor. It also incorporates a damping mechanism to reduce vibrations and extend belt life. Weighing 0.384 kg and measuring 0.152m in length, this tensioner is built for precise fitment and durability. Using a genuine OEM belt tensioner ensures optimal belt alignment, consistent tension, and effective vibration damping, which is crucial for preventing premature belt wear and accessory component failure.