ResMed AirSense 11 HumidAir HumidifierResMed HumidAir Humidifier Water Chamber for AirSense 11 This HumidAir water tank is only for use with the ResMed AirSense 11 CPAP machine. The humidifier adds moisture to your CPAP air pressure to increase comfort and prevent dryness in your nose, mouth and throat. Get the most from your HumidAir Tips to increase your humidifier lifespan: Only fill it with distilled or filtered water to ensure your CPAP supplies remain free of mineral build up and