Cobalt Micro Ceramic Rings are ideal for boosting biological filtration in any filtration systems. The rings are extremely porous, providing tremendous surface area for nitrifying bacteria to thrive. Included media bag allows for quick and easy replacement. The unique design promotes maximum water flow and oxygenation. They are ideal for use in reef, marine and freshwater applications. Micro Ceramic Rings provide 13700 cubic feet of total surface area.