These Ubbink filter media bags are designed to keep the filter medium of your choice contained in your filtration system. These Ubbink filter media bags present a convenient way to customise aquarium or pond filtration. These Ubbink filter media bags can hold carbon, ammonia remover resins, or any other type of filter medium. Keeping filter media in these media bags prevents the finer particles from being washed out and contaminating your filtration system. Made of nylon, the bags are highly durable. Delivery includes 2 pieces.