AquaClear 20 Activated Carbon Filter Insert improves water clarity for freshwater and marine aquariums, AquaClear 20 Activated Carbon Filter Insert provides superior adsorption qualities which eliminate odors, discoloration and impurities, It is designed to fit the AquaClear 20 Power Filter, The AquaClear 20 Activated Carbon Filter Insert Features and Benefits:, - Freshwater and marine aquariums, - Premium research grade, - Absorbs odors, discoloration, and impurities, - Improves water clarity, SKU: RCHG0434