Battery operated. Amplifier bandwidth extended for high frequency training when using 2.5SE software. 2 high quality amplifiers. Input impedance: 1000 GOhms; sampling accuracy: 0.4 microvolts; operating bandwidth: 0.5 -64.0 Hz-and is intended to be sampled at a rate of 256 samples per second or faster; CMRR: 120 dB minimum; interface to PC: optically isolated, serial or optional USB available; batteries: internal, rechargeable, optional external 9 volt battery back up available, AUX (HEG) interface standard. Robust, reliable, upgradeable, easy to use, the industry EEG workhorse. Supported by BrainMaster 2.5SE software release, the BioExplorer Enhanced Driver for BrainMaster; BrainMirror 1.2 and additional software in development. Researchers and practitioners who are working at 40 Hz and above (gamma band) training will find this device of value. It provides superior recording and feedback of fast EEG rhythms 256 sampling rate, provides high resolution recordings for assessment and training purposes.