The MATRIX System has 40 computer-assisted programs with the most advanced technology using specific pre-programmed software algorithms to bioelectrically trigger 3 different physiological mechanisms of actions. Frequency ranges from .01-250 pps,(with the ability to effect the nerves by stimulating or facilitating), but also using a High Definition frequency generator (HDfg)™ that can produce much higher frequencies (or pulses per second) from 5,000 pps, 8,300 pps to as high as 10,000 pps to inhibit (interrupt) the pain signals Price is firm. Unit like new.