3 stage reverse osmosis replacement filter pack for International Filter and GE 3 stage RO systems. Includes combination carbon/sediment pre-filter and GAC canister type post filter and 2 canister O-rings. Also works on most 3 stage reverse osmosis with canister type pre and post filters. Includes the service manual “How to Service Your Reverse Osmosis System” by Dionicio Porras. Service your RO system like a pro!