This powerful filter contains patented rotating Bio-Wheel technology to provide superior wet/dry biological filtration for nitrifying bacteria growth and eliminating toxic ammonia and nitrate fast. As it rotates the Bio-Wheel exposes beneficial bacteria to the air helping bacteria work harder and faster to keep your aquarium ammonia-free. All Bio-Wheel filters feature noise-reducing two-piece vented covers and adjustable mid-level intake strainers. Uses two Marineland Rite-Size E Filter Cartridges with Black Diamond Premium Activated Carbon to filter out dirt and debris for maximum water clarity.