Genuine OEM Audi V-Belt Tensioner, part number 038903315AE. This crucial component maintains proper tension on the engine's accessory drive belt, preventing slippage and ensuring the efficient operation of various engine accessories. Weighing approximately 0.87 kg, it is a robust assembly. Choosing a genuine OEM tensioner ensures factory-specified spring rates and pulley alignment, critical for preventing premature belt wear and maintaining optimal accessory drive system performance.