Features:* Single Channel Preamp.
* Clean, crisp sound amplification.
* Even, flat response.
* 9 volt battery powered.
* Long battery life (up to 1500 hours with an alkaline battery).
* Trim pot for setting preamp gain from 0 to 20 db.
* Input Impedance: Up to 10 M ohm.
* Output Impedance: Less than 3.5 k ohm
Further details can be found on the Schatten Website.