8"/200mm Plate Airstone for Koi Ponds & Aquariums, Air Stone for Larger Pump Bubble Diffuser for Outdoor Pond Garden Circulation System Aquariums, Aquatic, hydroponic, Fish Tank or Any Aeration Need. Fine Bubbles: The plate air stone disc produces lots of rich micro bubbles of oxygen. A great way to oxygenate your hydroponic growing systems, koi fish ponds, water gardens, aquariums and enliven the aquatic life and create a healthy habitat. Made of minerals that are sintered at a high temperature, to encourage longer lasting product. Perfect for both fresh and salt water environments like fish tanks, water gardens, bird baths, ponds, DWC reservoirs, aquariums and more. Airflow dependent on depth of Pond and output of airpump. Pump required, Not Included