The GE Merlin Reverse Osmosis Membrane # 1238342 is the replacement RO Membran The GE Merlin Reverse Osmosis Membrane # 1238342 is the replacement RO Membrane for the tankless GE Merlin Reverse Osmosis System. The GE Merlin RO System requires two of these membranes to operate. The GE Merlin RO Membrane TLC-350 has a packaged shelf life of approximately 8 months when refrigerated. The GE Merlin Reverse Osmosis Membrane Elements should be replaced every 2-4 years.