Fluval U4 G2 Underwater FilterFLUVAL U4 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. Now with new and improved design features! KEY FEATURES New sleek design New easy grip water control paddle New redesigned media cartridge Traps more debris Designed for aquariums up to 240 L (65 US Gal) Use as a primary filter for smaller