Watts Premier WP531411 531411, RO-Pure 4-Stage Reverse Osmosis Water Filtration System REVERSE OSMOSIS WATER FILTRATION: The Watts Premier RO Pure Reverse Osmosis System was designed with you in mind. With a space saving, compact design that allows the system to fit under your sink with minimal space requirements. It gives crystal clear, high quality and great tasting water. RO WATER FILTER: Changing the filters in this RO System is as easy as pushing a button, eliminating the mess and difficulty associated with filter changes! No need to shut off the water before changing the filters! There are check valves installed in each filter lid that will close the water flow when cartridges are removed. Maximum operating Pressure: 100 psi EASY TO INSTALL: Watts Premier's Reverse Osmosis home water treatment systems are easy to install. All components are an integral part of the unit, requiring fewer tube connections, Back-flow prevention valves are installed between the elements. Cartridges have double o-rings so they won't leak. FOUR STAGE WATER FILTRATION: The RO Pure Reverse Osmosis System consists of 4-Stages of filtration. Stage 1 - Sediment Pre-Filter (105311), Stage 2 - Carbon Pre-Filter (105351), Stage 3 - 50 GPD Membrane (105331) Stage 4 - Carbon Post-Filter (105341), giving you crystal clear, high quality and great tasting drinking water. BEST QUALITY WATER FILTER: Includes a Chrome, Monitored, Top Mount, Air-Gap Faucet and 3 gallon storage tank. Filters change out at the push of a button. This system is certified by WQA to NSF/ANSI 372 Lead Free and Certified to NSF/ANSI 58 Certified Reverse Osmosis Units.