When installed the 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.