Marineland Penguin Bio-Wheel Power Filter Aquarium Filter Cartridges, Rite-Size C, 6-packCategory: Nitrate Filter CartridgeFor more than 40 years, Marineland has been committed to fishkeeping success. By applying biological science, advanced engineering and imagination to fishkeeping, Marineland continues to be the leader in innovative aquatic environments & equipment. Today, that spirit of innovation is alive and well at Marineland. Whatever your passion — fresh or saltwater, big or small — count on Marineland to bring you the most reliable, the most technically advanced, the highest quality aquariums and accessories on the market. At Marineland, we design our filter cartridges to meet the absolute highest standards of water purification, performance, and operational ease. Each pre-assembled cartridge slides easily into place, providing superior mechanical and filtration, and making replacement fast, dry and effortless. The cartridge mechanically filters water through a pad of double thick poly-fiber. Debris and waste particles are trapped, and water is ly filtered through Marineland's Black Diamond Premium Activated Carbon. Inside the cartridge, a patented ribbed backing ensures even distribution of activated carbon to deliver maximum water-to-carbon contact. The result is crystal clear, crystal clean water.