DescriptionIf you are looking for a professional and affordable filter cotton for your external hanging fish tank filter , then your research is over here. That's because ourfilter cottoncan satisfy your need. It is easy and convenient for you to use. It will be the good choice for you.Features-Color:Black-Material: Sponge -Size: About7.50X4.50X3.50cm/2.95X1.77X1.38inch- Fine material and highly efficient filtration of impurities in water.- Purify your fish tank with this high density filter pad, a nice helper for you.- High-quality material does not pollute water and can keep water clean, no deformation, free cutting, good softness.- The filter pad has plenty of surface area to create superior biological filtration.- Effective to avoid residue and reduce the death rate of fish and chemical filtration and increase the oxygen solubility in aquarium and fish tank.