APEC Essence 5 stage complete filter set is made with high quality filtration components to protect and prolong the lifespan of your reverse osmosis system. Premium quality filter set lasts over 6 months for high performance contaminant removal, while the membrane and post carbon filter last 2-4 years. These standard size filters are compatible with APEC 50 GPD Essence and all other 10" standard size under counter reverse osmosis systems. APEC ROES-50 complete replacement filter set, compatible with most 10" standard under the counter reverse osmosis water systems 1st stage 5 micron sediment filter to remove dust, particles and rust 2nd and 3rd stage 10 micron extruded carbon block filter to remove chlorine, taste and odor4th stage high Rejection TFC reverse osmosis membrane removes a wide range of contaminants5th stage high capacity coconut shell carbon filter removes any last residuals