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. 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.
This product is no longer available. A suitable alternative to this device would be the AirCurve 10 VA BiLevel Machine. This auto-adjusting BiPAP automatically chooses the inhale and exhale pressures for you so you don't have to manually set either pressure. It also comes with a built-in heated humidifier for optimal therapy comfort.