2231027525_6415162309 Simple yet effective bio-filtration for a variety of tank sizes. Lee's Undergravel Filters feature adjustable uplift tubes and a semi-flexible; break resistant plastic body. Flat plate design allows for even water flow beneath the plate. Complete with a slim Discard-a-Stone air diffuser; fish saver elbow; and carbon cartridge; these undergravel filters offer efficient and economical filtration. Designed for use with a 29 gallon aquarium. For more information; read our article about Undergravel Aquarium Filtration.