It is a 75 GPD (gallon per day) membrane with Reverse Osmosis technology that uses the unique properties of a semi-permeable membrane to allow liquid to pass through while restricting the flow of dissolved ionic substances. It effectively reduces TDS and sodium as well as a wide range of contaminants such as arsenic, leads, percolates, chromium, copper, radium, and protozoan cysts including Giardia and Cryptosporidium. Reverse osmosis technology When pressure is applied to impure water next to such membrane elements, pure water leaves most of the impurities behind.