Fostex HPA4 DAC & Headphone Amplifier

This is the Fostex HP-A4.
Included accessories are two instruction manuals, a USB cable, and the original box.
Confirmed to produce sound properly on a PC.
I believe there are no noticeable scratches on the main unit.

DAC & Headphone Amplifier HP-A4
Brand: FOSTEX

Headphone amplifier with high-quality DAC functionality.

- Model: HPA4
- Output Terminals: RCA
- Input Terminals: USB, RCA
- Filter Settings: ULTRA, LINE
- Gain Settings: 2.8m, 5.5m
- Digital Output: Yes
- Country of Manufacture: Japan

Operates via USB bus power.
Capable of playing Linear PCM audio up to 24bit/192kHz and DSD audio up to 5.6MHz.
*To play DSD audio, DSD-compatible playback software for your computer is required. This unit supports DoP and ASIO methods.
Supports a wide range of headphones with HI/LO gain switching (10dB).
Employs asynchronous mode using custom crystal oscillators.
Equipped with a digital filter that allows switching of roll-off characteristics and cut-off frequencies according to the audio source.
Features a high-quality DAC (Burr-Brown PCM1792A).
Supports USB Audio Class 2.0