Genuine OEM Volkswagen Ultrasonic Sensor Retainer, part number 3C5919491M. This small plastic component is designed to securely hold an ultrasonic sensor in its correct position within the vehicle's assembly. It is typically found in the rear of the vehicle, supporting parking or proximity sensors. Made from durable, lightweight plastic, it weighs only 0.007 kg. Using a genuine OEM retainer ensures the sensor is mounted precisely, preventing movement or misalignment that could affect its accuracy and overall system performance.