Easy-to use biological filter for tropical aquarium fish Aquarium filter sponge for efficient biological filtration Supplying the water much needed oxygen Most fit to external or top filter as prefiltration unit No deads spots in cylinder foam offers increased filtration Various types of installations are possible The sponge material is easy to clean Quiet operation Beneficial bacteria colonize sponge filter for waste breakdown, Recommend tank size: 20-40 gallons Dimension : 11.5-inch (with tube) , Sponge Height :5.5-inch ; Material : Sponge, Plastic