The XBBWMRS 9 Pack Large Aquarium Replacement Filter Cartridges by Tétra are designed specifically for fish tanks and aquariums. These filter cartridges are designed to efficiently remove impurities and contaminants from the water, ensuring a clean and healthy environment for fish. Made with high-quality carbon material, these cartridges effectively eliminate harmful chemicals and microorganisms, providing a safe environment for aquatic animals to thrive. The pack of 9 cartridges ensures a steady supply of clean water for your aquarium, making it a convenient and essential addition to any fish tank setup. Open box.