Genuine OEM Audi Alternator Poly V-Belt, part number 045903137D. This crucial belt transmits power from the engine's crankshaft to drive the alternator and other vital engine accessories, such as the power steering pump or air conditioning compressor. Weighing 0.16 kg, this multi-ribbed belt is engineered for optimal tension and long-term durability. Using a genuine OEM belt ensures the correct material composition, length, and rib profile, which is essential for preventing slippage, reducing noise, and maintaining the reliable operation of all driven components.