This is the Matrix Mini-Portable, a compact Amp and DAC solution that gives you desktop quality audio everywhere you go. The Matrix Mini-Portable features a 24bit/192kHz DAC over optical (24bit/96kH over USB) and an amplification circuit powerful enough to drive headphones up to 300 Ohms. Add in the 8 hour battery life and you've got an exceptional portable amp that you can use as a complete desktop headphone system. Incredible utility, solid build, and exceptional price make this an obvious choice for any nomadic audiophile.