Enjoy cleaner, refreshing water with the PUR 3-Stage Universal Reverse Osmosis (RO) Filtration System. Install this 3-stage RO system under your sink to deliver more purified water through a secondary air gap faucet. Forget bottled water and opt for an environmentally sound water filtration system that is NSF certified to reduce at least 15 unwanted contaminants including lead, cysts, TDS, and heavy metals. During stage 1, the 5-micron carbon block filter reduces particulates and chlorine. In stage 2, the RO membrane further filters to less than 0.0001 microns, thereby reducing chemical contaminants and improving the safety of your drinking water. In the final 3rd stage, a secondary carbon block filter removes any residual taste that may come from the storage tank. For best system maintenance, replace the carbon block filters every six months and replace the RO membrane every two years. Features a compact, bracket-mounted design with everything you need for quick and easy installation.