I just posted my review of the HM-801. Click Here to Read

If you don't know what it is - here are some specs -

Modular Design: Modular Amplifier Bay (Named GanQi Bay) and 14.8 volt Lithium Polymer Battery Bay
Memory: SDHC Card
Volume control: ALPS Analog Attenuator
DAC function: Coaxial (16bit 44.1kHz to 24bit 96kHz) , USB DAC (16bit 48kHz)
DAC Chip: Burr-Brown PCM1704;
Op-Amp: OPA627 Exchangeable Module Battery

Music Format Support:
APE Fast、Normal、High Mode
AAC 16K-320Kbps
FLAC lossless VBR 16bit and 24bit
WMA 8-355kbps
OGG Quality 0-Quality 10
MP3(VBR) 8-320Kbps