This is a printable enclosure for the open source, DIY O2 headphone amplifier, designed by NwAvGuy: http://nwavguy.blogspot.com/2011/08/o2-details.htmlO2 was designed to fit a Box B2-080 aluminum housing. The front panel of the O2 has two 3.5mm jacks, a power LED, a power switch, gain switch, DC jack, and a volume knob. To actually use the intended aluminum case, you'd need precise tools and machining skills...This design is an easier DIY solution for the O2. Note that the case body is simpler and narrower than the B2-080 case. The front panel is thus slightly wider than the printable enclosure body, but was modeled to fit both this 3D model, or the actual B2-080 aluminum body.1) Print one each of the "O2 Case No Hump" and "O2Front for BOX enclosure". 2) Slide finished O2 PCB into freshly printed case. 3) Affix caps to pushbuttons (2x) 4) Secure front panel to case with self-tapping M3 screws. Depending on the calibration and accuracy of your 3D printer, you may need to touch up the holes with an exacto knife to achieve proper fit. 5) Attach volume knob to potentiometer shaft.