GE Osmonics Desal TFM-100 Reverse Osmosis Membrane Drinking water filtered by reverse osmosis provides a superior quality of purity right from the tap 100 gallon per day replacement membrane, for large quantities of clean drinking water daily Be sure to match the correct flow rate of the membrane with the flow rate of your RO system, for peak efficiency Great return on your investment: replace the TFM-100 membrane approximately every 2 years, depending on water quality and your usage