Complete filter set (membrane not included) for APEC 5-stage reverse osmosis system is made in the USA with the highest quality filtration components to provide a longer lifespan of the reverse osmosis membrane. Premium quality pre-filter and post-filter cartridges last 12 months for high-performance contaminant removal. Compatible for APEC RO-90, RO-permeate, and all other standard sizes under counter 50-90GPD generic RO systems. 1st stage: high-grade 1 micron, 10 inch high-capacity polypropylene sediment filter – removes dust, particles, and rust. 100% pure polypropylene depth filter with exceptional dirt-holding capacity translates to longer life 2nd and 3rd stage: premium extruded carbon block 10 microns 10 inch – gets rid of unpleasant chlorine, chloramine, tastes, odors, cloudiness, and colors. Also removes VOC and other common chemicals from the water. Carbon block filters consist of activated carbon particles fused into a uniform block with enhanced adsorptive capacity and efficiency. Unlike granular activated carbon (gac) filters, these extruded carbon block cartridges will not channel or bypass due to the extreme uniformity of their extruded activated carbon core. 4th stage RO membrane (not included). 5th stage: advanced coconut shell refining carbon 10 inch – TCR (Total Contamination Removal) filter removes any possible residual taste from the tank.