The Myron L RO-1 DS Series Handheld TDS Meter has been the choice of professionals for years, this compact instrument has been designed specifically to demonstrate and test point of use (POU) reverse osmosis or distillation systems. By measuring electrical conductivity, it will quickly determine the parts per million/total dissolved solids (ppm/TDS) of any drinking water. With a single “before and after" test, this handy device effectively demonstrates how your RO or distillation system eliminates harmful dissolved solids. It will also service test systems, including membrane evaluation programs.