6” (152mm) diameter (Dome) – Heavy duty Sintered Airstone for pond or large pool. Aeration is a important part of pond care, maintaining oxygen levels and helping fish stock levels. Air stones allow oxygen to get to the roots of the plant. By adding Aeration stones you improve water quality and circulation. Aeration stones are called air stones, discs, bubblers or diffusers and come in many shapes, sizes, colors and coarseness levels. Made of porous stone, its main purpose is to gradually diffuse micro air bubbles through your water with the help of a pond pump and tubing. They do not clog and give a better distribution of air with finer bubbles than other types of aeration systems. Spherical and cylindrical shaped airstones are also available in a range of sizes. Sintered airstones are very durable and extremely easy to clean. They are safe for all types of lakes, ponds, fresh water aquariums, salt water or marine fish tanks.