USB connector on your computer or laptop and drawing all the power they need from there, no no need of batteries or a separate amplifier.
Altec Lansing Orbit USB Stereo Speakers These USB powered speakers look almost like artillery shells, but instead of an explosion, the pint-sized audio components pack a sonic wallop for just $50. We like the hidden cord storage and the fold out stands that tuck away for easy travel storage when used with the included carrying case.
UCube Digital Speakers What we really like about these tiny speakers, is the high quality materials they are made of and the different array of colors that you can get them. The brushed aluminum stand is very sleek. They are great for home or office use and the superb sound quality makes it a good choice for movies and videos. DSP-controlled power supplies and DSP-equalized signals for the very special BMR Balanced Mode Radiator driver deliver an astounding 170 degrees of stereo image so everyone can enjoy the experience. 15 Watts RMS of power.
Lacie Bobourg USB Speakers The new LaCie Bobourg USB Speakers provide excellent sound for your laptop or desktop PC or Mac computer. They come with a built-in USB cable and touch-sensitive volume control placed in the front panel of the speaker, so you don't have to go and find the small knob on the back of the unit to control the output. With a Class D digital amplifier, and a neodymium driver, the LaCie Bobourg USB Speakers provide great sound quality at an affordable price.
Bowers & Wilkins MM-1 Speakers A very compact design with incredible sound quality. DSP tuning keeps bass effect powerful and rich while using Nautilus drive unit technology for accurate sound reproduction. USB connection makes it a snap to get you ready to go.