Descriptions:OOTDTY With a airlift system, super biochemical sponge filter features silent operation, and has an excellent filtering effect while oxygenating the water, the social 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. Features: High-quality aquarium sponge filter for efficient biological filtrationSupports large bacterial populations to break down aquarium wasteDense, high-quality foam ensure reliable longer lasting aquarium useDo not trap fish fry and are safe for small size fish such as dwarf cichlid, guppy, killifish, etc. Specifications:Material: Plastic+Biochemical Sponge+MetalColor: BlackHeight: 12cmDiameter: 5.5cmQuantity: 1 SetNote:1.Transition: 1cm=10mm=0.39inch2. Please allow 0-3cm error due to manual measurement. pls make sure you do not mind before you bid.3.Due to the difference between different monitors, the picture may not reflect the actual color of the item. Thank you! Package Contents:1 x Biochemical Sponge Filter1 x Plastic Hose