The Fluval Universal Filter Mesh Bags made of nylon are the ideal bags for filling with loose filter media such as peat fibers, filter peat granules, activated carbon, or zeolite; practical and clean. The handy Fluval Universal Filter Mesh Bag prevents premature wear of the filter motor and fits perfectly into the Fluval filter media containers of the Fluval suction filter as well as the Fluval MSF external filter. The Fluval Universal Filter Mesh Bag is, of course, also suitable for other filters. Packaging includes 2 bags.