Fluval U Series Underwater Filters (A460-A480)3 Stage Filtration With Biomax For Superior Aquarium Water Quality, Flip Top Accessfor Quick And Easy Cartridge Replacement And Three Way Flow Control Make The Newfluval U Series The Benchmark In Underwater Filtration. Fluval Underwater Filterswith Three Stage Filtration Are Ideal For Use In Fresh, Marine Or Reptile Environments.Stage 1 Foam Removes Large Particles.Stage 2 Poly/Carbon Cartridge Traps Fine Debris, Improves Water Clarity And Removesimpurities.Stage 3 Biomax Provides Optimal Biological Filtration Efficiency. For Aquariums, Terrariums And Turtle Tanks Ideal Supplemental Or Stand-Alone Filter, Or For Installations Where External Filtration Is Not Possible Filters Debris And Provides Optimal Biological Filtration Silent And Efficient Simple To Install And Maintain Engineered And Manufactured In Italy