Genuine OEM Audi Differential Vent Hose Elbow Fitting, part number 02W525118. This small, angled fitting is designed to connect the vent hose to the differential assembly. Its function is to allow the differential to breathe, equalizing internal pressure while preventing the ingress of water and contaminants. Weighing approximately 0.009 kg, this precision-engineered component is crucial for maintaining the differential's health. Using a genuine OEM fitting ensures a perfect seal and correct hose routing, protecting the differential from premature wear and failure.