Check the listing for details. RainSoft UF22 Compatible RO Filter Kit (Membrane Sold Separately). Condition: New. Listed at 27.98 USD. 1-Year Filter Replacement Kit for RainSoft UF22 Reverse Osmosis System (RO Membrane Sold Separately) INCLUDES: * STAGE 1 - 1x Carbon Block Pre Filter (OMB934-5M) - Replace Every 12 Months * STAGE 2 - 0x (RO Membrane TFC-RS9-22 Sold Separately or Included with Replacement Kit YSM-RSUF22) - Replace Every 24 Months * STAGE 3 - 1x Carbon Block Post Filter (OMB934-5M) - Replace Every 12 Months Note: If your Rainsoft reverse osmosis system is from 2013 or newer, it most likely is the Ultrefiner II. The Ultrefiner II requires proprietary filters that must be purchased from a Rainsoft dealer. Conversion kits to generic non-OEM replacement filters are available. Filters may need to be replaced more often than indicated depending on incoming water contaminant levels and volume of water being treated.