Xin You Black Thick 4.5 cm Aquarium Tank Biochemical Filter Cotton Set XY-1028 Product Specifications: Dimension: 60x45x5 cm Material: Sponge Product Usage: 1) This product can be used for seawater tank, freshwater tank and waterweeds tank with the sizes being cut as your wish. 2) According to tot the analysis of the experts, products with this pore gap and flexibility and the most suitable breeding grounds for cultivating the fine nitrobacteria. 3) The biochemical cotton has the best effect on decomposing the excrement and the forage leftovers and improving the filtering and cleaning of water, it can reduce the death rate of fish. 4) Being cleaned with water once per month, without blocking and deforming, it can be used again after cleaning can be repeated for use up to 16 times. Product Contents: -1x Xin You Black Thick 4.5 cm Aquarium Tank Biochemical Filter Cotton Set XY-1028