Genuine OEM Volkswagen Engine Control Chain Tensioner, part number 03H109467A. This critical component is responsible for maintaining the correct tension of the engine's timing chain. It ensures precise valve timing and prevents chain slack, which can lead to engine damage. Constructed from durable metal and high-strength polymer, it weighs approximately 0.132 kg. Choosing a genuine OEM tensioner ensures factory-specified spring rates and material quality for optimal chain longevity and engine performance.