Description: 100% Brand New and High QualityColor:As the pictureMaterial:SpongeNote:1.This product is suitable for sea water tanks, fresh water tank, water plants cylinder, the size of the free cut.2.secret hole clearance and softness is most suitable to cultivate a hotbed of good nitrifying bacteria through expert analysis3.biochemical cotton decomposition of excreta and feed residues, improve water quality filter clean. The best results. Reduce fish mortality.4.regular cleaning! (About 10-20 days to wash) can be reused after cleaning. Included: 2 x 2 Layer Biochemical Filter Sponge