Total RMS output: 1.5 watts Total peak power: 3 watts Power supplied by USB port from desktop/notebook Selected 50x50 mm speakers for clear sound Glossy front panel Volume control Works great with any computer system using a standard 3.5mm audio plug Compatible with Win7, Vista, XP, Mac 10.0 or above  Don`t be limited by a power adaptor, 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. 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. The cable length between the two speakers is approx 90cm. The USB cable and Jack cable length are both approx 110cm.