For users who do not want to use the humidifier option on the AirSense 11 and save space, the ResMed AirSense 11 side cover can be used in place of the humidifier tub. The humidifier options will be disabled when the side cover is in use.
Fit perfect easy to use.if you don't need water this is the way to go.i will use it when I travel the most ,don't have to carry water.also with the cover on you don't have to clean the water tank.