Genuine OEM Audi Timing Chain Guide Rail, part number 059109507AN. This critical engine component is designed to guide the timing chain, ensuring its correct path and preventing slack or excessive movement. It works in conjunction with the chain tensioner to maintain optimal chain tension and precise valve timing. Positioned within the engine's timing assembly, it is typically made from a durable, low-friction polymer or composite material. A genuine OEM guide rail ensures the correct dimensions, material properties, and wear resistance for reliable engine operation and longevity.