Includes 1 filter: for 3M Aqua-Pure Whole House Large Diameter System AP904 with up to 100,000 gallons of filtration capacity. To maximize system performance and efficiency, please replace every 12 months, at the rated capacity, or sooner if a noticeable reduction in flow occurs. Filter life is dependent on actual use and incoming water quality. Triple Stage Filtration: Featured with 0.5 micron small pore size, PERCOLA filters are equipped with Triple Action Filtration. First stage non-woven media captures the larger particles, then in the second stage, the pleated sub-microns membrane reduces particles as small as 0. 5 microns, and finally, the carbon block reduces chlorine taste, and odor and select VOCs. Top Quality:The filter consists of a 1/4-inch plastic housing, 2 layers of pleated filter media, and an approximately 1-inch activated carbon inner solid core. The cartridge also includes a scale inhibitor media to help reduce hardness scale that can build up in water heaters, pipes, and water-using appliances. Easy Change-outs: With Sanitary Quick Change (SQC) design, it allows for fast and easy cartridge change-outs (just a quarter turn) without having to contact the filter media or the need for a filter wrench. Filter change-outs only take a few minutes and you don’t have to spend extra hundreds of dollars on a hiring plumber and replacing the filter cartridge. Steady Water Flow: PERCOLA AP917HD-S whole house water filter is designed to flow at the rate of your faucet (up to 10 gallons per minute), minimizing water pressure loss commonly seen with using water filter, which guarantees a stable and fast water flow.