The industry's first hang-on filter with integrated U.V. Sterilization, self-adjusting surface skimmer and replaceable filtration media, the AQUATOP PFUV-40 Power Filter is capable of filtering up to 128 gallons per hour with an adjustable flow rate. Suitable for freshwater and saltwater aquariums up to 40 gallons, this convenient "Hang On Back" style filter has a built-in, self adjusting surface skimmer for cleaning the surface of the water and to promote gas exchange. The featured UV Sterilizer of the PFUV-40 requires no extra plumbing, allowing for a quick and easy installation. The UV Sterilizer of the PFUV-40 helps eliminate unwanted algae blooms, keeping aquarium water crystal clear and aids in the health of your aquatic creatures by eradicating free-floating parasites. The PF-UV Series fits on aquarium rims up to 3/4", and comes equipped for mechanical and chemical filtration. With a replaceable filter pad enhanced with AQUATOP's Bamboo Carbon, UV Sterilization and a self-adjusting surface skimmer, the PFUV-40 is a one-of-a-kind filter for all your aquarium needs.