Mr. Aqua UV-C 9 watt UV sterilizer. Great for aquariums up to 100 gallons. Powerful 9 watt UV bulb, equipped with mechanical filter pads and pump. Will rid of green water, nuisance, parasites, bacteria, and viruses. The Mr. Aqua UV-C 9 watt UV sterilizer also helps with surface skimming to reduce surface film.