The Aqueon Replacement Large Filter Cartridge is designed to maintain optimal water quality in your saltwater aquarium by removing impurities and harmful substances through its high-quality activated carbon and dense floss material. This cartridge features a dual-sided design with over 25% more activated carbon compared to leading brands, ensuring an even distribution of the carbon for superior filtration performance. It is easy to install—simply rinse under cold water and align the key slot on the bottom of the cartridge into your Aqueon QuietFlow Filter's designated area. This product is ideal for maintaining a healthy aquatic environment in aquariums that use the specified filter models, ensuring clear, clean water for both your fish and coral.