Aquarium Sponge Filter, Powkoo Bio Filter Sponges Foam Filter Quiet Air FilterPowkoo sponge filters provide mechanical filtration, biological filtration, oxygenation, aeration in one, these sponges are high density porous 80ppi fine sponge, protect baby fish from being sucked into the filter system, and also makes good water flow, which can ensure the excellence of the water quality, helps your small fish or shrimp to live a happy, healthy life, suitable for freshwater and saltwaterFits fish tank size: 5 to 20 gallon 2pcs 7