Don"t be limited by a power adapter, Genius releases cute mini speakers, SP-U115, whose power is supplied through a USB port from a desktop/notebook. They use 50mm speaker drivers for loud and clear sound performance for a total of 1.5 watts RMS. Four glossy front covers to choose from: shiny black, sapphire blue, ruby red, or grass white. It has a convenient knob on the side to adjust the volume. Just insert the USB plug to a PC/notebook for power and the 3.5mm audio plug into music playback device, such as a PC, notebook, MP3 or CD player and enjoy music with the SP-U115.