The RENA SmartFilter is revolutionizing the power filter category by bringing the superior filtration of a canister filter to the back of the aquarium. The RENA SmartFilter offers unparalleled functionality, including unique pressurized filtration so water flows through not over the filter cartridge. The 4-sided filter cartridge contains Bio Chem Zorb, the most advanced filtration resin available, to deliver crystal clear water. The SmartFilter also features the most convenient cartridge replacement system, with a universal, one-size-fits-all cartridge. The revolutionary cartridge caddy is easy to access and features a drip-reduction cup. Plus, the RENA SmartFilter offers 3 levels of filtration: mechanical, chemical and biological for maximum cleaning power, and it combines with the RENA SmartHeater (sold separately) to offer an integrated filtration and heating unit for less aquarium clutter. A truly innovative design from RENA.