Genuine OEM Volkswagen Toothed Belt Pulley, part number 0XW109111B. This pulley guides and supports the toothed belt, ensuring proper tension and alignment. It is located at position 9 in the diagram. Proper functioning of the pulley is critical for maintaining the correct tension and alignment of the toothed belt, which is essential for accurate engine timing. Genuine OEM pulleys are manufactured with precise tolerances for smooth operation and longevity.