The AirCurve 10 S is a Bi-Level CPAP Machine with continuous fixed pressure. The bi-level machine has two different, adjustable set pressures which can make therapy feel more comfortable for patients who needs extra pressure support. The AirCurve 10 S also comes with an integrated humidifier, that makes sleep therapy even more comfortable. Patients have better success using a humidifier with their therapy, keeping the nose and mouth from drying out through the night. This item number comes with ClimateLine Air to enhance your comfort and help prevent moisture from accumulating in the tube.