Genuine OEM Audi Belt Tensioner Pulley, part number 06M903315K. This component is an upper tensioning element designed to maintain proper tension on the engine's accessory drive belt, ensuring smooth and efficient operation of various engine accessories. It prevents belt slippage and reduces wear on other components. Weighing 0.298 kg with a diameter of approximately 0.1m, this pulley is built to precise specifications. Choosing a genuine OEM tensioner pulley ensures factory-specified bearing quality and tensioning force, critical for reliable belt system performance and longevity.