The AP217, AP217-2, 5578604 3M Aqua-Pure Under Sink Replacement Water Filter Cartridge Set (2-Pack) is a dual action filter for use with 3M Aqua-Pure's compact under-sink water filtration systems. Under sink water filtration systems are great solutions to provide cleaner, clearer and great tasting drinking and cooking water by reducing a wide range of contaminants that may be present in the local water. The AP217 is a short, round cartridge with a grooved resin-bonded pre-filter on one end, and an encased granular carbon post-filter with connector on the other end. Under sink water filtration systems are great solutions to provide cleaner, clearer and great tasting drinking and cooking water by reducing a wide range of contaminants that may be present in the local water. This under sink replacement water filter cartridge is NSF listed to reduce chlorine taste and odor. The AP217 replacement cartridge is for use with the space saving, compact design AP200 water filter system and also reduces sediment.