The upgraded Microtubes B7K Ultra with Aux in features: (1) Single user loadable cabinet simulation impulse response. (2) Micro-USB B port to connect to PC/Mac to load a different Virtual Cabinet through the Darkglass Suite. (3) 3.5mm headphone output with cabinet simulation. (4) Balanced XLR output with switchable cabinet simulation. (5) A 3.5mm stereo input that allows you to practice with backing tracks from e.g. your smartphone or laptop.