SunSun HW-302 3-Stage External Canister Aquarium Filter 264GPH Canister filters for aquariums use high water pressure, from a properly powered pump, to force water through the dense filter media. A pump can draw water from an under-gravel filter, and run it into a canister for double filtration 3 media trays capable of handling your choice of filtration media; Comes with an adjustable spray bar. This is a helpful feature if you want to adjust the output flow from the filter Convenient self-priming pump that eliminates the need for manual siphoning; Single valve disconnect & priming pump ease routine maintenance Provides quiet, efficient filtration for fresh and saltwater aquariums is great for living rooms, offices or bedrooms