Genuine OEM Audi Engine Timing Chain Guide Rail, part number 057109467G. This guide rail works in conjunction with the tensioner to maintain proper alignment and tension of the engine timing chain, ensuring precise valve timing. It is located within the engine's timing system. Weighing 0.035 kg, it is constructed from durable, low-friction material. Using a genuine OEM guide rail ensures correct chain path and reduces wear, preventing premature failure of the timing system.