The Marina 360/Splash Replacement Filter Cartridge, with carbon and zeolite, improves water clarity and color while removing polutants and odors. This replacement filter cartridge is designed for use with the Marina 360 Aquarium and the Marina Splash Aquarium. The Marina 360 / Marina Splash Replacement Filter Cartridge comes in a package of 4.For more fish tank accessories check out the other Marina products including aquarium filters, filter media, aquarium heaters, aquarium air pumps, aquarium lights, aquarium decorations, aquarium gravel, aquarium rocks, aquarium thermometers, and aquarium stands. Marina has a wide variety of products that are perfect for your pet fish or betta fish to enjoy in any large fish tank, small fish tank or in a freshwater tank.