The Seltz D are AC controllable universal pumps, with innovative 6 pole electronic motor for energy savings. The pumps are controllable through the enclosed electronic controller to increase or decrease the flow at 6 preset points. The controller has a maintenance mode to pause the flow of the pump for feeding or maintenance inside the aquarium. Seltz D pumps are suitable for saltwater and fresh water use. The pumps can be used in-line or submerged, they are equipped with sensors that detect the presence of water moving through the pump so it will shut off to prevent damage. Extremely quiet operation and wear-resistent ceramic shaft. For use as return pumps, circulation pumps, fountain and pond applications.