It is made of polyester cotton material, which can be reused many times, and can be easily cut into any size required with scissors, with high utilization rate. Our aquarium filter mats are ideal for freshwater or seawater aquariums, and can be used for wet and dry filters, pumps, filters, waterway systems, etc. The three dimensional weaving process is not easy to form an oxygen layer, and the filtration has a certain cultivating effect at the same time. This fish filter has an excellent filtering function. The aquarium filter is absolutely safe for all fish and other organisms. This fish filter cotton is made of high quality filter material, high strength, washable, not easy to deform, and simple to clean.