The Nuforce uDAC-2 is a portable high-performance USB DAC meaning Digital Analog Converter as well as a headphone amp all together in a tiny package. When I say portable I mean it's tiny enough to be portable but you cannot use it with your iPod on the go because the uDAC-2 does require USB power and does not have any batteries making it the best friend your laptop can have and saving you some desk space. Why do you need one of these you ask? Check out the full review after the break where I'll go over similar questions.