Genuine OEM Audi Engine Serpentine Belt Tensioner, part number 07K903315AB. This critical component maintains proper tension on the engine's serpentine belt, ensuring consistent power delivery to accessories like the alternator, power steering pump, and air conditioning compressor. It is located within the engine's accessory drive system. Weighing 0.693 kg, this tensioner is constructed from durable materials for long-lasting performance. Using a genuine OEM tensioner guarantees correct belt tension, reduces belt slippage and noise, and prevents premature wear on the belt and associated pulleys.