This replacement set contains the 1 year supply of the following filter cartridges:

• Stage 1 - 5 micron NSF polypropylene sediment pre-filter to extract suspended materials such as sediment, silt, rust, and other particles down to 5 micron. (Replace every 6-8 months) - 2 Pieces

• Stage 2 & 3 - 5 Micron NSF Activated Carbon Block - High purity coconut shell activated carbon block filter reduces sediments, taste, odor, color, chlorine and its byproducts such as THM and TCE, low levels of hydrogen sulfide (rotten egg smell) that cause bad odor, PFASs such as PFOA & PFOS, SOCs, and VOCs. (Replace every 6-8 months) - 4 Pieces

Age of the filters depends on GPD consumed and quality of feed water.