Pentek (161079) 4-Stage RO-2550 Reverse Osmosis System 50 GPDPentek 4 Stage Reverse Osmosis System The Pentek RO 2550 50 GPD delivers exceptional water purity for residential point of use applications Four stage filtration with GE Desal 50 GPD thin film composite membrane removes contaminants down to 1 1000 of a micron. NSF certified for salt and dissolved mineral reduction. 50 GPD Capacity NSF Certified TFC Membrane 2. 8 Gal Tank FILTRATION STAGES Four stage process for comprehensive contaminant reduction