Genuine OEM Volkswagen O-Ring, part number WHT009139. This O-ring is a circular seal used to prevent leakage in brake hoses and pipes. It is designed to create a tight seal at connection points within the brake system. The O-ring has a diameter of approximately 45mm and a thickness of 4mm. Genuine OEM O-rings are manufactured to precise specifications, ensuring reliable sealing and preventing brake fluid leaks, which is essential for safe and effective braking.