The Cartridge Filter Kit with Holder and Check Valve provides 12 months of worry free operation for some of the most popular sleep equipment sanitizing machines on the market, it can perfectly compatible with So Clean 2. The Kit provides the highest quality materials to keep your sanitizing units in top operating condition. Quick & Easy Installation - Quality and size are exactly as the original supplied equipment, Just remove the old filter and replace it, No need to dismantle the unit and easy to keep your machine running at top performance. Excellent cleaning effect - Upgraded Check Valves manufactured to exceed original equipment. It prevents water from the machine from damaging electronics. And the Filter Holders with active carbon filters Reduce bad ozone odor left in your equipment! The cartridge filter can better absorbs ozone released and make your sleep equipment ready for use sooner.