Genuine OEM Volkswagen Rear Brake Pad Wear Sensor, part number 7P0907637C. This sensor is designed to monitor the thickness of the brake pads and alert the driver when they have worn down to a critical level, indicating the need for replacement. It is specifically installed on the rear brake assembly. This small electrical component weighs approximately 0.018 kg and has a length of 14 cm. Using a genuine OEM sensor ensures accurate wear detection, proper electrical connection, and reliable performance, which is crucial for maintaining braking system safety and integrity.