1 Year Supply: 7 pcs Reverse Osmosis Replacement Filter set (Sediment x 2, GAC x 2, CTO x 2, Inline T33 Post filter - 1 Total filters: 7. Universal 1 Year Supply Replacement Set for Undersink 5-Stage Reverse Osmosis Water Purification Systems Stage #1: 10" Sediment Filter, 5 Micron. Removes dirt, silt, sand, rust and scale particles. Stage #2: 10" 10" GAC Granulated Activated Carbon Filter. Removes chlorine, chloramine, VOCs and etc. Stage #3: 10" CTO Carbon Filter. Removes chlorine, chloramine, VOCs, bad taste and odor, 5 micron Stage 4: 50 GPD USA Made membrane, Stage 5: 5 Micron Inline filter with T33 carbon