Easy plug and play installation. USB bus powered--requires no external power. Stereo headphone output lets you jam with your computer and can also be used for monitoring with active monitor speakers. Plug  in your  favorite guitar and  turn your PC or Mac computer  into a guitar amp and  recording system without the need for any other hardware. High-quality components and exceptionally rugged construction ensure long life. Variable-speed  file playback  function for MP3, WAV, AIFF audio files perfect  for easy learning and practicing.