Marineland Penguin BIO-Wheel Power Filters deliver easy, three-stage mechanical, chemical and biological aquarium filtration. Convenient Penguin Rite-Size Filter Cartridges come ready to use with each filter...ready to mechanically and chemically remove waste, discoloration and odors. Contains new Black Diamond Premium Activated Carbon for maximum efficiency. Biological filtration is provided by the revolutionary, patented BIO-Wheel - proven best at removing toxic ammonia and nitrite. The filters feature noise-reducing two-piece vented covers and adjustable mid-level intake strainers.