Genuine OEM Audi Engine Upper Timing Chain Tensioner, part number 06E109217AN. This critical engine component, located on the left side, is responsible for maintaining the correct tension on the upper timing chain, ensuring precise valve timing and smooth engine operation. Made from durable metal with a specialized low-friction shoe, it prevents chain slack and reduces wear. Weighing 0.68 kg, its factory-specified tension and robust construction are essential for the longevity and reliable performance of the engine's valvetrain.