This RO 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 - 5 Micron NSF Activated Carbon Block - High purity coconut shell activated carbon block filter reduces sediments, taste, odor, color, SOCs (soluble organic compounds) and VOCs (volatile organic compounds), and chlorine and its byproducts such as THM and TCE. (Replace every 6-8 months) - 2 Pieces

• Stage 3 - High quality NSF 50 GPD Reverse Osmosis Membrane: Removes 99% contaminants present in water. (Replace every 2 years) - 1 Piece (optional)

• Stage 4 - In-line Post Carbon NSF GAC filter removes dissolved gases, bad taste and odor from product water. This is the final polishing stage before consumption. (Replace every 1 year) - 1 Piece

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