With an airlift system, super biochemical sponge filter features silent operation, and has an excellent filtering effect while oxygenation the water, the special developed foam materials supports the colonization of bacteria, allowing for mechanical filtration in addition to biological filtration, which will break down harmful waste, ammonia and nitrite material, resulting in a cleaner living environment for your fish, particular they are useful for as breeding filter or as secondary filter Most fit to external or top filter as purification unit No dead spots in cylinder foam offers increased filtration Easy maintenance is made by nodular design of foam cartridge system