The Tetra EasyCrystal Filter Pak with Carbon 3-Pack is a highly efficient and convenient filtration system designed to keep your aquarium water clean and clear. This product is specifically designed for use in freshwater and marine aquariums, providing exceptional water quality for your aquatic pets. Each filter pack in this 3-pack bundle contains a combination of mechanical and chemical filtration media, including activated carbon. The mechanical filter captures large particles and debris, ensuring that the water remains free from visible impurities. The activated carbon plays a crucial role in chemical filtration by effectively removing impurities, odors, and discolorations from the water, resulting in crystal-clear and odor-free aquarium water.