Genuine OEM Audi Engine Belt Tensioner, part number 05L903305E. This essential component is responsible for maintaining the correct tension on the engine's accessory drive belt, which powers vital systems like the alternator and air conditioning. It also helps to dampen vibrations for extended belt and component life. It is located within the engine's accessory drive system, often near the alternator. Weighing 1.12 kg and measuring 0.228m in length, this tensioner is engineered for robust performance. Using a genuine OEM belt tensioner ensures precise belt alignment, consistent tension, and effective vibration control, preventing premature wear and potential system failures.