Genuine OEM Volkswagen Door Window Regulator, part number 3AE839407D03C. This part guides the window as it moves up and down within the door assembly. It is positioned in the door frame, specifically at location 19 on the diagram. This regulator features a rally black finish, indicated by the '03C' suffix. Genuine OEM regulators ensure precise fitment and smooth window operation, crucial for maintaining the integrity of the door seal and preventing rattles.