Replacement filter set for 3 Stage Reverse Osmosis Revolution Black Series 3 Stage Water Purifier 1st Stage: 10" Sediment Filter, 5 Micron. Removes dirt, silt, sand, rust and scale particles. 2nd Stage: 10" CTO Carbon Block Filter. Removes chlorine, chloramine, VOCs, bad taste and odor. High quality guaranteed. 5 Micron Rating 3dr Stage: 10" inline Omnipure (USA) CLIROT33 GAG filter, 5 Micron Rating Service life: 12 months.