APEC Water Essence high capacity pre-filter set (FILTER-SET-ES) includes (1) sediment and (2) carbon block filters to protect and extend the life of the RO system. 1st Stage: 5 micron polypropylene sediment filter to remove dirt, particles, and rust 2nd & 3rd Stage: 10 micron extruded carbon block filters to remove chlorine, taste & odor High performance replacement filters are compatible with APEC reverse osmosis systems ROES-50, ROES-75, ROES-PH75, ROES-PHUV75, ROES-UV75, ROES-UV75-SS and all other standard sized under counter RO systems.