This Universal Power Supply will automatically adapt to voltages in most countries worldwide. (A plug adapter may be required for use outside of North America.) It is the only power supply that should be used with AirSense, AirStart or AirCurve sleep therapy devices. Using a non-ResMed power supply with a ResMed CPAP or BiLevel machine may damage it and void the manufacturer’s warranty. For complete instructions review the documentation that came with your equipment.