AudioQuest DragonFly Black

USB Stick-Sized Digital-to-Analog Converter
Plays all music files: MP3 to high-res
Compatible with Apple and Windows PCs, as well as iOS and Android mobile devices (requires Apple Camera Adapter or Made for Android/OTG adaptor)
Drives headphones directly
Fixed output feeds preamp or AV receiver
Asynchronous transfer ensures digital timing integrity
Medium output (1.2 volts) drives a wide range of headphones
32-bit ESS 9010 DAC with minimum-phase filter
Analog volume control