Genuine OEM Volkswagen O-Ring, part number N91001001. This O-ring is a circular seal with a square cross-section, used to create a seal between two mating surfaces. It is located at position 15 in the diagram. The O-ring has a diameter of 0.068m. Genuine OEM O-rings are manufactured to precise tolerances to ensure a reliable seal and prevent fluid leakage in critical engine systems.