Sufficient quantitythe package contains 30 pieces aquarium filter media bags in white color, each one measures approx. 15 X 20 cm, applied for fine resins filter and activated carbon for fresh or saltwater tanks Fine meshthe aquarium filter bags adopt fine mesh design, and the mesh diameter is 100 micra, which is suitable for most fish tank filter materials without spilling Aquarium media bagthese 15 x 20CM highflow filter bags are suitable for most fish tank filter materials, such as activated carbon, biochemical ball, ceramic ring, bio ball, coral bone, volcanic stone, and other rough media Quality materialthe aquarium filter bag is made of quality nylon, which is durable and reusable after cleaning The drawstring closes the bag tightly and prevents the loose flow of media that could damage your pump Zipper pocketsthe aquarium filter bags are designed with a zipper closure at the opening, which is compared with the traditional drawstring design, the zipper seal not only makes it convenient to replace the filter material