MECO Biochemical Sponge Filter Breeding Fry Shrimp Aquarium Fish Tank Air Pump XY2820 Sponge filters provide both mechanical and biological filtration Simply install an air line into the unit and provide both aeration and filtration for your fish Aerobic bacteria colonize the sponge providing a bacterial substance to facilitate the nitrogen cycle Product dimension: 9L x 4.8W x 13Hcm Sponge dimension: 4.8D x 6Hcm