10 Watt Ultraviolet Clarifier can be used either fully submerged or in-line. Has glowing “Halo Ring” that indicates that the clarifier is working. Vortex flow design creates longer water exposer time to ultraviolet light. Includes transformer with 18′ grounded cord. Includes one 9000 hour, long life 10 watt lamp and water tight quartz sleeve. Has 3/4″ barbed fitting on in-let and outlet.