Genuine OEM Audi Camshaft Control Chain Guide Rail, part number 066109509A. This component provides a smooth, low-friction surface for the camshaft control chain, guiding its movement and contributing to precise engine timing. It is an integral part of the engine's timing system, often working in conjunction with a chain tensioner. Made from a durable, wear-resistant polymer with a metal bushing, it weighs approximately 0.066 kg and measures 0.147 meters in length. Choosing a genuine OEM chain guide rail ensures the correct material properties, precise dimensions, and optimal wear characteristics for reliable and quiet operation of the engine's timing chain.