APEC ROES-100 complete replacement filter set, compatible with most 10" standard under the counter reverse osmosis water systems 1st stage sediment filter to remove dust, particles and rust 2nd and 3rd stage extruded Carbon block filter to remove chlorine, taste and odor 4th stage high rejection TLC reverse osmosis membrane removes a wide range of contaminants 5th stage standard capacity coconut shell Carbon filter removes any last residuals