This Easy Pure RO membrane is a 75-gallon-per-day filter that removes TDS and sodium from water. Its reverse osmosis technology restricts the flow of dissolved ionic substances, resulting in purified water leaving most of the impurities behind as well as reduces contaminants such as arsenic, lead, percolate, chromium, copper, radium, and protozoan cysts including Giardia and Cryptosporidium.