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. TimeStrip color tabs included with each filter cartridge tell you when it's time to replace them. 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 .