Traps Floating Debris And Protect Your Baby Fish From Being Sucked Up Into The Filter,Aerobic Bacteria Colonize The Sponge Providing A Bacterial Substance To Facilitate The Nitrogen Cycle.Aquarium Sponge Filters Has Two Media Containers With Ceramic Bio Filter Media Inside Of Each,Will Help To Remove Harmful Substance And Increase Oxygen Level In Your Tank,You Can Replace The Filter Media To Enhance Water Quality.Scientific 5-Layer Ribbing Shape Sponges Design,It Quickly Established A Bio-Filter And Extra Oxygen,Two Sponges Means More Surface Area For Beneficial Bacterial To Colonize And Faster Cycling,Keep Your Fish Tank Crystal Clear And Clean.Easy To Install:Simply Install An Airline Into The Unit And Turn On The Air Pump,Great Way To Clean And Oxygenate Your Tanks;Easy To Clean.Aquarium Sponge Filters Comes With 2 Suction Cups,Can Be Installed Anywhere And Can Be Easily Hidden On The Back Wall Of The Aquarium;Suitable For Shrimp Tank,Betta Tank,Breeder Tanks,Goldfish,Discus,Guppies,Fry,Baby Fish Or Other Fish.Color:blue+greenmaterial:plasticSize about:19 x 7.5cmSpecifications:Xy-2881Package Contents:2 x Fish tank filterOnly the above package content, other products are not included.Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.