This is the reverse osmosis filter set for standard residential drinking water systems. If your system looks similar to either of the pictures on the right hand side, you have the standard 4 stage system.(a very popular system) Included in the set is the 5 Micron Sediment, a 10 micron carbon block, and a 10" inline GAC cartridge. You should change your RO filters every 12 months to maintain the highest quality of water and extend the life of your system. The membrane is not included in the set as it needs to be changed every 3-4 years. If you need the membrane, we have it in the store for your convenience. Look for the TW30-1812-50 membrane made by Filmtec for your system. It is the recommended choice.