What's included ? 4 pieces of 5 micron sediment filters: With only a five micron rating, it is effective in removing dirt, rust and sand particles. NSF certified. 4 pieces of granular activated carbon (GAC) filters: Adsorbs chlorine, halide, organic contaminants, odors, and other impurities that contribute to bad taste and odor. 4 pieces of 5 micron carbon block filters: Removes any remaining chlorine and organic chemicals. Further enhances the taste of water. 1 piece of 500GPD Dual-Flow reverse osmosis membrane: A thin film composite (TFC) high quality membrane that processes 500 gallons per day at a 1:1 waste ratio, best in the market. The membrane is tested and certified by NSF International. 2 pieces of post carbon inline filters: This post carbon filter removes objectionable tastes and odors to enhance the quality of your drinking water.