This 50 gal per day residential reverse osmosis membrane kit consist of a semi permeable membrane which effectively reduces total dissolved solids and sodium as well as a wide range of contaminants such as arsenic, lead, perchlorate, chromium, copper, radium and protozoan cysts, giardia and cryptosporidium. The heart of the reverse osmosis system reduces impurities down to 1/10000 of a micron.