This is the 30 Watt external power supply for use with the ResMed S9 Series CPAP and BIPAP machines when used WITHOUT the humidifier.
This product includes four (4) different adapters to plug into the wall outlet to work in the United States and abroad. Select the appropriate plug for your location. This power supply is smaller and lighter than the 90 Watt version used to power both the machine and humidifier.