The Marineland Emperor Rite Size E Cartridges Filters are designed for fish tanks and aquariums, with a flow rate ranging from 280 to 400GPH. These bio wheel filters fit Marineland tanks with capacities of 280, 400, and 450 gallons, and can be used with all types of water. The lot of 4 new open cartridges includes models PA0137-04, offering external filtration for your aquatic needs.