This Beckett biological pond filter is the perfect addition to your fountain, koi pond, small pond, waterscape, statuary, and other types of water displays. This filter is most compatible with Beckett's pump models G210/G250 or G325/G355 . The biological media balls help grow beneficial bacteria to naturally balance your water feature. Your water display will be healthy as ever with this filter helping keep your pond clean and making the water look crystal clear. The bio filter is easy to place into your pond and just as easy to remove for cleaning. The filter is especially great for reducing clogged fountain nozzles. Keep your water display clear, healthy, and a beautiful look with the help of this filter. Pump not included.