Genuine OEM Audi Camshaft Chain Tensioner, part number 058109217B. This critical engine component is responsible for maintaining the correct tension on the camshaft chain, which is essential for precise valve timing and smooth engine operation. It prevents chain slack, which can lead to timing inaccuracies and potential engine damage. Weighing 0.623 kg, this tensioner is built for durability and consistent performance. Installing a genuine OEM chain tensioner ensures factory-specified spring rates and damping, providing reliable tension and extending the service life of the timing chain system.