Genuine OEM Volkswagen Brake Fluid Reservoir, part number 1K1611301E. This essential component is designed to hold the brake fluid supply for the master cylinder, maintaining the hydraulic pressure required for effective braking. It is typically mounted on top of or adjacent to the brake master cylinder. Weighing 0.267 kg, its precise dimensions (0.15m L x 0.145m W x 0.115m H) ensure a perfect fit. Using a genuine OEM reservoir guarantees proper fluid containment, material compatibility, and leak-free operation, which is critical for brake system safety and reliability.