Genesis Water Technologies CSCB5-20 Coconut Shell Carbon Block Replacement Filtration Cartridges in The Standard 20-Inch X 2.5-Inch Size Natural coconut shell carbon block replacement filter is excellent for a pre or post filter for a reverse osmosis system Designed to remove chlorine-VOCs-pesticides-hazardous chemicals and offensive odors Standard 20 inch by 2.5 inch size is interchangeable with most manufacturers Five micron rated filtration filter is NSF certified Proudly Made in America