Woo Audio WA7d Fireflies Duo with WA7tp (tube power supply) upgrade in Black High Performance 100% Vacuum Tube Design Headphone Amplifier with DAC 32-Bit, 192kHz DAC for high resolution audio playback Ultra quiet 1/4" and 3.5mm (for IEM) headphone outputs, Hi/Lo Impedance switch Multi-functional switch for USB input, optical TOSLINK Input and RCA input Avaliable in Black or Silver color, High clarity glass top for tubes protection