The world famous Whisper power filter updated for the 21st century. The Whisper EX20 aquarium power filter offers a host of modern conveniences and advanced filtration capabilities to keep your aquarium clean, clear and healthy. Extra-quiet, in-tank motor design promotes even quieter Whisper operation, eliminates priming and lowers the filter's profile. Rounded filter chamber design promotes circulation and reduces sediment build-up. Enhanced biological grid promotes optimum bacteria growth. Squeeze-to-open filter cartridge design keeps your hands clean when performing regular cartridge changes. Whisper EX20 is designed to filter aquariums up to 20 gallons with a flow rate of 110 gph. Requires 1 medium size Whisper Filter Cartridge .