The AC/DC 12V 30A Fish Tank Aquarium Automatic Water Supply Controller comes with an integrated Water Level Sensor, which automatically senses the water level and automatically activates the solenoid valve to dispense water when necessary, ensuring your fish tank stays at the perfect level of hydration. The Circuitry is designed to protect against electrical surges and short circuits, preventing any potential damage to your equipment. The Water Pump Motor Switch ensures a steady and reliable water flow, preventing frequent starts and stops, making your aquarium maintenance a breeze. This product is truly a smart addition to your aquarium setup, promoting a healthier and more vibrant environment for your aquatic friends.