The Tunze Metering Pump for Osmolator 5000.020 is a reliable replacement dosing pump specifically designed for the Osmolator automatic refill system. Operating at low voltage (3-12 V DC), this dosing pump ensures efficient and precise water level regulation in your aquarium. It is compatible with 4 mm (.2") hose and operates optimally at 12 V, providing consistent performance and accurate dosing. With its durable construction and compatibility with the Osmolator system, this metering pump offers a seamless solution for maintaining the desired water level in your aquarium.