Genuine OEM Audi Tandem Brake Master Cylinder, part number 6R1611019B. This crucial hydraulic component is responsible for converting the mechanical force from the brake pedal into hydraulic pressure, which then actuates the brake calipers or wheel cylinders. It is typically mounted in the engine bay, connected to the brake booster. This specific cylinder is configured for Left-Hand Drive (LHD) vehicles and weighs approximately 0.59 kg. Using a genuine OEM brake master cylinder ensures precise hydraulic pressure delivery, optimal braking performance, and long-term reliability, critical for vehicle safety.