mainly composed of multi-stage high-pressure pump, reverse osmosis membrane element, membrane shell (pressure vessel), flow meter, bracket, etc. The pore size of the reverse osmosis membrane is 0.0001 micrometers (μm), and only water molecules can pass through, and its solute cannot pass through the reverse osmosis membrane, so as to meet the physical and chemical indicators and hygienic standards prescribed by drinking, and produce clean to pure water.