This aquarium filter media serves mechanical filtration to catch fine
particles and biological filtration for raising good stuff Ceramic media
covered with thousands of porous tiny holes provides large surface area for bio
filtration as well as filter out sparkling clear water Aquarium media block
effectively absorbs fish waste and debris, providing crystal clear water for
fish to thrive Package include: 40 pack ceramic blocks; Size of each block:
3.8" x 1.18" x 1.18" Crack into pieces to any size needed, great for used in
freshwater aquariums, planted aquariums, sumps and ponds. (Not suitable for
saltwater aquarium)