Why are only some masks compatible with AirMini?

AirMini / Masks

ResMed's ActiveAir technology regulates vent flow as pressure increases, reducing the total flow budget while maintaining the same quality of therapy with a smaller blower. Additionally, moving the vent from the mask to a location further down the tubing allows locating the HumidX/HumidX Plus heat-moisture exchanger on the patient side of the vent. This helps capture more of the heat and moisture expelled by the patient on exhalation, improving the humidification experience. Because of the ActiveAir technology and HumidX/HumidX Plus, only certain masks are compatible with AirMini, have the correct venting to work with the AirMini.