The GK™425 is a Bilevel device which delivers 2 levels of pressure, offering another option to the treatment of the Obstructive Sleep Apnea (OSA) patients. Equipped with the Flow Sens technology, an optimal patient-to-device synchronization is obtained to improve patient comfort. Summary data, usage data and respiratory rate are recorded in device memory and can be downloaded and processed by the Silverlining3 PC software.