Classic series canister filters have the longest most reliable track record in the trade. A pump/motor unit that seems to run forever with a minimum of service. Proven technology, balanced performance, and high efficiency mark classic series filters as the bellweather in aquarium filtration. One chamber design allows for the greatest flex in setting up for mechanical, biological, chemical and adsorptive filtration. Flow rates have been precisely calculated to provide the exact balance needed between mechanical and biological long-term filtration, water circulation and oxygen enrichment, resulting in optimum conditions for successful aquarium keeping, with 3-6 month maintenance intervals. Also ideal for specific purpose filtration such as Chemical /Adsorptive (carbon).