Features 1.Filter cotton is eco-friendly, soft, durable and will not deform for a long-term use 2.Excellent water permeability makes it avoid blockages and provide the largest adhesion area for bacteria, cultivate the nitrifying bacteria for biological filtration 3.The filter can decompose the excrement and the forage leftover effectively, leaving the fish fresh water to breath 4.Dense shape makes it effective to avoid residue, and the filter can be cut any sizes as you needed 5.Lightweight design with multiple thick holes is very suitable for using in fresh water and marine water Specification Description: Adopting the biological filtration technology to filter the blockages, excrement, the forage leftover etc that can not been seen with our eyes. The purpose is to keep the water in fresh, clean condition, reduce the burden of digestion system. Features: Filter cotton is eco-friendly, soft, durable and will not deform for a long-term use. Excellent water permeability makes it avoid blockages and provide the largest adhesion area for bacteria, cultivate the nitrifying bacteria for biological filtration. The filter can decompose the excrement and the forage leftover effectively, leaving the fish fresh water to breath. Dense shape makes it effective to avoid residue, and the filter can be cut any sizes as you needed. Lightweight design with multiple thick holes is very suitable for using in fresh water and marine water. 3 kinds of different thickness filters for you to choose according to your habit. Specifications: Material: Filter Cotton Color: Black Optional Size: Approx. 50 * 50 * 2cm/ 19.7 * 19.7 *0.8 inch, 50 * 50 * 4cm / 19.7 * 19.7 * 1.58inch, 50 * 50 * 5cm / 19.7 * 19.7 * 1.97inch Package Weight: Approx. 95-310g Item Type: Aquarium Filters Function: Filter The Blockages, Excrement, The Forage Leftover etc Package Include: 1 x Aquarium Filter Sponge Only Package List