This compact DC to AC inverter has been tested by all CPAP machines (NOT including ResMed S9 series). For ResMed S9 series, please use ResMed DC/DC Covnerter for S9 Series Machines.
Very Important: Using a heated humidifier with a DC Inverter is not recommended and can damage your humidifier and /or CPAP machine.
Return On Warranty Issues or Mask Assurance Purchase Only.