Like new condition iFi Nano iDSD. Portable DAC and headphone amplifier that can pretty much play any file format you send at it. Pretty cool what they packed into this device. MSRP $189. I am the original owner.
I used it on my Windows 7 machine with USB2.0 ports. Does not work with MacBook Pro (late 2013) due to a known issue with USB3.0 standards not followed by Apple and possibly other manufacturers. iFi-audio is working on a firmware fix that should be ready within a month or so.
How I used it:
iPhone 4S > CCK adapter > Onkyo HF or Apple music app > iDSD or > iDSD > amp
PC > JRiver > iDSD > amp
Selling because it was a fun experiment/distraction, but there is too much redundancy in my rig.