The Filter Pro Black Coarse Filter Media is custom designed for use in aquariums, ponds and other outdoor water garden applications. It can be cut to any size for multiple filtration applications. The custom fiber weave design filters out unwanted debris and contaminants for crystal clear aquarium and pond water. It also provides an immense surface area which is ideal for beneficial nitrifying bacteria. Our Black Coarse Filter Media is tough enough to handle heavy debris like sticks and leaves, while still providing a high flow-rate required for oxygenating the large volume of water flowing through the filter systems or skimmer for your aquarium or ornamental pond. This means healthy water conditions, and healthy aquatic plants, koi and other fish! This filter media is extremely durable and is also reusable. It can easily be rinsed out and reused many times. Made in USA.