The R.O. (Reverse Osmosis) water filter system is a layered filtration system, that is, it filters coarse sediment first, then filters the taste, odor, and color until a solution with a size not exceeding 1 micron is left, then passes it through a filter called a membrane., as fine as 0.0001 microns, is similar in size to a water molecule. which germs with a size of 0.22 microns (the smallest) cannot pass through and can filter up to 96% of various chemicals and toxins. The R.O. filtration system is one of the most efficient water filtration systems available currents.