SMSL M3 High-End USB Audio DAC with integrated headphone amplifier. Includes 9,8 feet (3 meter) flat USB cable + cinch splitter + small micro USB cable.
The unit was for an audio product but in the end of the development phase got disregarded for the particular product (cost too high). Manufacturer (SMSL) stopped production of the DAC last year, very hard to get. Super crisp sound (many reviews available online). Can be connected with a computer, Apple phone or tablet, Android phone or tablet and even gaming consoles. Can also be powered by a power bank or directly via USB when connected to a phone or computer. The unit was only tested once, like new. 
 
Specs:

Aluminum alloy shell, solid aluminum buttons and knobs

DAC chip: CS4398

Channels: 2

Output power level: 1.9 Vrms

THD+N: < 0.006%

Dynamic range: > 112 dB

SNR: > 107 dB

Channel separation: > 105 dB

Sample rate, USB: 96 kHz (24 bit)

Sample rate, optical and coaxial: 192 kHz (24 bit)

Output power, 108 mw: 32 ohm at THD 0.1%

Output power, 85 mW: 64 ohm at THD 0.1%

Output power, 49 mW: 150 ohm at THD 0.001%

Output power, 24 mW: 300 ohm at THD 0.001%

Inputs: USB, optical, coaxial

Outputs: Line, headphone amp