Take portable humidification to a whole new level The F20 HumidX was designed specifically for the AirFit F20 AirMini setup pack for the AirMini Travel CPAP Machine. These packs are small heat and moisture exchangers (HME) that are designed to provide comfortable and effective humidification. When you exhale, heat and moisture is captured and stored within the HME’s tiny paper ridges. When you inhale, this heat and moisture is released to humidify the air you breathe in. Each HumidX cartridge is usable for up to 30 days after opening. The HumidX is inserted between the mask and the vent, providing compact waterless humidification at a comfortable level.(mask not included) Compatibility: Only the AirFit F20 set up pack is compatible with the F20 HumidX waterless humidification units. *The F30 Full Face mask, N20 and N30 nasal masks and P10 pillow masks are not compatible with this item.