Aqua-Pure AP817-2 Water Filter Cartridge SIZE 4.5IN X 4.5 IN X 20IN helps reduce chlorine taste and odor as well as particulate and rust, providing clearer, more appealing water throughout the whole house. The carbon filter cartridge provides a high flow for up to six months before replacement. It is for use with the following Aqua-Pure systems: AP802, AP802-1.5C.The cartridge is manufactured by 3M Purification Inc., formerly CUNO Incorporated. It uses granular activated-carbon media to reduce chlorine taste and odor, has a 25-micron filtration rating for particulate reduction, and a flow rate of 20 gallons/75.7 liters per minute. The cartridge operates at temperatures from 40-100F/4.4-37.8C.. The cartridge should be replaced every six months, or sooner if a noticeable reduction in flow rate occurs. Whole-house water treatment systems range from simple canisters with disposable filter cartridges to complex systems of tanks and filters for different contaminants. A system that includes a water softener may be bypassed by a cold drinking water line to provide salt-free drinking water. Whole-house systems are typically installed immediately after water meters and well pumps, and thus may be referred to as point-of-entry (POE) systems. Depending on the filtration and treatment processes, they remove or reduce iron, particulate, chlorine odor and taste, and other chemical and biological contaminants. In doing so, they help protect plumbing and fixtures, reduce unpleasant tastes, colors and odors; and, in some cases, provide healthier water.