Delta Clarifi™ Reverse Osmosis Water Filter Replacement CartridgeClarifi Reverse Osmosis uses high pressure to push water through the systems four layer reverse osmosis filter, in addition to the pre filter and carbon filter, to remove 90+ contaminants from your drinking water. Designed for easy DIY maintenance, the carbon and RO filters and optional remineralizer cartridge have a two year lifespan so you can quickly and easily replace them at the same time, and it takes less than a minute to replace each filter.