Fluval Underwater FilterFluval Underwater Filter Offering outstanding 3 stage filtration, increased water movement and vital aeration, Fluval U Series internal filters are the perfect solution where external filtration is not possible. New Sleek Design New Easy Grip Water Control Paddle New Redesigned Media Cartridge Traps more debris Use as a primary filter for smaller aquariums, or supplementary filter for larger aquariums Position horizontally for shallow tanks, larger