I had this just lying around, never used. Installed two fresh 9V batteries, but I have too many portable amps and this never saw any action, still back in the box. Condition 10/10 (new). $89 shipped via PP gift within CONUS vs. $149 to $189 sale price on this unit. http://www.poppulse.com.hk/Product%20poppulse.html Factory specifications: Frequency response.dB 20hz-40khz +-0.05dB Noise level,dBA >100dB Dynamic range,dBA >100dB THD,% >102dB Stereo crosstalk,dB>105dB POWER 32ohm >1.8W Magnification 20dB It's a little bigger than an iPod Touch and can reportedly drive both IEMs and larger cans as well for about 20 hours on 2x9V batteries. Overall, size is roughly similar to the RSA SR71A.