The Lifegard Aquatics UV Bulb of highest quality pure hard quartz material allows maximum UV transmission and longer bulb life. The end cap wire design drops bulb further into unit for maximum output and keeps heat away from sealing area. The test tube style quartz sleeve isolates UV bulb from water contact allowing it to operate at the optimum bulb temperature for maximum UV output. UV light, when used properly, is extremely beneficial in destroying disease causing pathogens as they pass through the unit. UV sterilization is an effective method of disease control and kills free floating algae in ponds resulting in crystal clear water. Its Modular Construction allows simple connection to any Lifegard Modular filter system or outside canister filter.