This GE Merlin Reverse Osmosis Replacement Activated Carbon Block Cartridge Filter is the Pre-Filter replacement for all GE Merlin Systems. This filter will remove chlorine, bad taste, bad odors, and sediment down to 5-microns to protect the membranes of the GE Merlin Tankless RO System. For general sanitary reasons, and to keep your Merlin running efficiently, this filter should be changed at least every 6 months.