Genuine OEM Volkswagen Belt Tensioner Pulley, part number 04L109243D. This component is crucial for maintaining the correct tension on the engine's drive belts, which power various accessories like the alternator, power steering pump, and air conditioning compressor. It prevents belt slippage and reduces wear on the belts and associated components. Weighing 0.619 kg, this genuine OEM tensioner pulley ensures factory tolerance for smooth, vibration-free operation and extended service life of the belt system.