MULTIPLE CHOICE SELECTION A OUTPUT: 1.5, 3, 4.5, 6, 7.5, 9, 12VDC @ 300mA Heres a device that conserves batteries conveniently and reliably on most equipment. Adaptor plugs into ordinary 120VAC 60Hz house current. Choose any of the above voltages. Has built-in polarity reversal switch. Employs a full wave bridge rectifier, with 1000mfd filter capacitor for good regulation and lowest hum level. 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. UL Listed.