Features: â¢Factory calibrated to 32 KHz of frequency. â¢Safe & user friendly with easy to follow instructions. â¢Velcro wrist bands, and special silicon-graphite-rubber electrodes. (No paper towels needed). â¢Automatic electrode control will sound a warning signal if not fitted correctly. â¢LED timer (7-20-7-20-7). 7 minutes on, 20 minutes off for three continuous sessions. â¢Choice of continuous mode, LED indicator, plus a reminder to renew the 9 Volt battery. â¢Warning beep will sound when contact is broken or insufficient. â¢Belt clip and carry case.