AquaClear Activated Carbon Filter Inserts feature ultragrade activated carbon that will improve your aquariums water color, clarity, and odor without changing the waters characteristics. Safely removes chlorine, smoke and aerosol spray contaminants.AquaClear Premium Research Grade Carbon InsertsAbsorbs odors, discoloration and impuritiesImproves aquarium water qualityAquaClear Activated Carbon Insert superior adsorption of impurities and broad spectrum organic compound removal make it one of the best inserts in the market. Supports beneficial bacterial colonies and can be used in both fresh and saltwater aquariums.Specifications:20 Gallon: 5-20 gallon aquariums30 Gallon: 10-30 gallon aquariums50 Gallon: 20-50 gallon aquariums70 Gallon: 40-70 gallon aquariums110 Gallon: 60-110 gallon aquariums