The Proton is for desktops, home audio, travel whatever! The idea is to make a dac that could run without a power supply and still sound wonderful. The idea is simple: we can use the USB power to provide for the necessities and then for the critical areas the LiION battery can supply the extra clean power for the dac and the headphone outputs. The Proton supports 24 bit data at 44.1, 48, 88.2 and 96k and is indicated on the rear by four leds. The volume control icon for the headphone output will appear on the computer desktop. Setting the volume slider on the computer will result hardware in the Proton to set the analog volume control for the outputs to the desired setting.