GC Electronics 30-6012 --  UNIVERSAL AC / DC ADAPTER, 500 MA OUTPUT

POWER SUPPLY, 120V / 60Hz AC INPUT, UL LISTED

selectable output DC voltages of 3V, 4.5V, 6V, 7.5V, 9V or 12V

includes these interchangeable power connectors (see photo):
  - 3.5mm male phone connector
  - 1.35mm x 3.5mm barrel connector / coaxial power connector
  - 1.5mm x 5.5mm barrel connector / coaxial power connector  
  - 2.0mm x 5.0mm barrel connector / coaxial power connector
  - 2.1mm x 5.5mm barrel connector / coaxial power connector
  - 2.5mm x 5.5mm barrel connector / coaxial power connector