Cartridge Filter Kit includes a replacement filter and check valve for SoClean 2. Filter and check valve should be replaced every six months. Cartridge filter kit only, SoClean 2 sold separately.
Cartridge filter converts activated oxygen back to regular oxygen as it leaves the SoClean 2 chamber. Check valve prevents water from CPAP machine damaging your CPAP.
SoClean filter cartridge's new design (particularly the check valve) is made thinner than the original. This design ensures a snug fit. A small piece of the black tube may require trimming to accommodate the wider diameter of the old check valve to insert the new one.