EXTRA HEAVY DUTY MULTIPLE CHOICE SELECTION - OUTPUT SELECTION: OFF, 3, 4.5, 6, 7.5, 9, 12VDC @ 800mA Six interchangeable plugs are included with the unit to serve most power-up needs. The plugs are: 2.5mm, 3.5mm, 2.1mm x 5.5mm, 2.5mm x 5.5mm, 1.35mm x 3.5mm, 1.7mm x 4.0mm & 9 volt snap adaptor. Plug-in Polarity Reversal Plugs into 120VAC / 60Hz house current 6-1/2 foot cord Circuit employs full range bridge rectifier with filter capacitor for excellent regulation and elimination of AC hum Inch .