Aquarium Sponge Filter Set XY-1038

100% Polyester Non-Woven Filter Media for freshwater and marine water or outdoor pond
Color: Black Dimension: 17.5 x 17.5 x 2 (thick) inch
Can be cut any sizes as your needed.
Cultivate the nitrifying bacteria for biological filtration.
Its multi-porous feature will avoid blockages and provide the largest adhesion area for bacteria.