The Pentair Aquatics Lifegard Aquastep 15 Watt UV Sterilizer is for aquariums up to 120 gallons15 Watt UV lamp. Unique 4 pin connector for easy bulb replacement without shutting down the system.In line or hang-on useConnections: 3/4" FPT. Comes with 1/2" hose barb fitting and 4 feet of hose. Inlet and outlet at top for hang on and at bottom for below aquarium installations.Requires an approx. 450 gph pumpDimensions: 21" X 7.5" X 3"Clear View Port. Allows visible light (no UV) to pass through and indicate bulb is operating adjustable clamp.Spring loaded clamp creates a snug fit to any aquarium or reservoir tank