Electric sponge filter with powerful motor, no need air pump; Just plug it in, it worksSponge filter provide both mechanical and bio filtration, also, the air infusion chamber produces minute bubbles which increase the oxygen solubilityNew Design: two media containers with ceramic ball inside, you can also replace this ceramic media with other mediaComes with 2 spare sponges, put them in the filter box, please take out the spare sponges before useRecommended tank size: 40Gal; Size of sponge: 2"Dx4.3"H Features: Electric sponge filter with powerful motor, no need air pump Just plug it in, it works Sponge filter provide both mechanical and bio filtration, also, the air infusion chamber produces minute bubbles which increase the oxygen solubility New Design: two media containers with ceramic ball inside ,you can also replace this ceramic media with other media Comes with 2 spare sponges, put them in the filter box, please take out the spare sponges before use Safe for fish: soft sponge material, traps floating debris and won't suck up your fish Excellent for small size fish like betta, dwarf cichlid, guppy, killifish, glofish etc., or for hatcheries, maternity tanks, nano tanks and fry tanks, as the filter produces minimal current and has almost no way to suck the fish through the filter Includes: 1 piece of sponge filter