The product consists of 50 simple and practical bio-filter balls, which have a plastic construction with high-performance cotton filling and are ideal for supplying oxygen to your water and gas exchange. Equipped with a mesh bag for storing these bio balls. Easy to rinse and use, porous design, improves the filtering effect of bacteria, lightweight and easy to carry. The filter balls provide a large surface area for bacteria and thus achieve a very high level of efficiency for natural biological filtration. A sufficient quantity can meet your different needs. Aquarium Filter Bio Balls that are excellent for oxygenating your water and facilitating the gas exchange process. A valuable aid in restoring natural water quality and providing the most suitable living environment for fish. Ideal for any freshwater or saltwater aquarium, or mini reef tank. As water flows through the internal space, the time is increased by using nitrifying bacteria to achieve the biochemical filtration effect. Pond filter balls do not need to be replaced, only if they are damaged or destroyed. Suitable for UVC filters, external filters, or filter tanks in aquariums or ponds. It is ideal for supplying water with oxygen and performing gas exchange. It can help create a comfortable living environment for aquatic life. Specification: Material: Plastic + Cotton Color: Black Diameter: 2.6cm/1inch Quantity: 50pcs