Genuine OEM Audi Alternator Voltage Regulator, part number 077903803D. This essential electrical component is responsible for controlling the output voltage of the alternator. It ensures a stable and consistent power supply to the vehicle's electrical systems and prevents overcharging or undercharging of the battery. Weighing approximately 0.122 kg, this compact regulator is designed for precise integration with the alternator. Opting for a genuine OEM voltage regulator guarantees correct electrical specifications and reliable performance, protecting sensitive electronic components and extending battery life.