This is a BiLevel machine which differs from a CPAP in that it switches back and forth between two pressure levels, one higher and one lower, rather than providing one continuous pressure level. The pressure upon inhalation is higher to hold the airway open, but as the user exhales, the pressure drops to a preset lower level. The GoodKnight 425ST BiLevel comes with FlowSens technology that helps optimize therapy effectiveness through controlled breathing. By allowing CPAP users to set the device's sensitivity, the flow-based detection system compares CPAP user data with a delayed air flow to trigger inhalation and exhalation breaths. The FlowSens technology provide a unique custom device can compensate air flow on a breath-by-breath basis.

A BiLevel machine responds well to people with very high CPAP pressure needs, weak chest wall muscles, lung disease or other health problems that keep them from being able to exhale against a CPAP pressure. The Puritan Bennett GoodKnight 425ST model comes with a Backup Rate that will initiate a cycling process of exhalation to inhalation if the CPAP user's breathing rate falls below the prescribed ratio.

• Smallest, lightest Bilevel, BiPAP or VPAP
• SilverLining software compatible
• International power supply
• Direct DC operation
• Automatic altitude compensation
• Two washable, reusable pollen filters
• 2 year manufacturer warranty against defects.