When installed the SoClean's Cartridge Filter converts activated oxygen back to regular oxygen as it leaves the SoClean device. The Check Valve prevents water backflow from your CPAP humidifier into the SoClean 2 device or CPAP electronics.
USAGE: Both the Cartridge Filter and the Check Valve must be in place at all times when using the SoClean 2 CPAP Cleaner & Sanitizer. For best results both items should be changed on average every 6 months. The SoClean 2 device will alert you when it is time to change the filter. This package is designed for use with all SoClean machines that have 1200SC in the serial number.