This Culligan Compatible Smart Pack IF2-HDG-CB-AC10 contains 2 Carbon block filters (1 year supply). The IF2-HDG-CB-AC10 Carbon Filter is a pre- and post-filter for various reverse osmosis systems. Created for superior absorptive efficiency, the Culligan replacement cartridge is used in Culligan Reverse Osmosis systems: AC15, AC30, LC50, and H83. This carbon block filter will remove the taste and odor associated with chlorine in your water. Also removes rust, dirt, sand, sediment and more. This pack does not include the Sediment filter (IF4-HDG-SED-AC5) for Pre filtration. The Sediment filter is sold separately. This pack will last 1 year. It is recommended to change your filter every 6 month. Please follow the instructions in your user manual to change the filters.