Multiple frequency zappers are superior to single frequency devices. Rife machines are similar because they can only emit one frequency at a time.
The Thundervolt zapper combines three frequencies into a primary waveform, and crushes parasites between it and a secondary waveform whose frequency shifts within a range of 250,000 cycles. This second output is automatically controlled by the electrical characteristics of the user's body during the zap session. The user does not have to guess about what frequency to use.
We also have a Body Tester that measures the effectiveness of zapping and gives the user a number of his or her life force. Visit us at https://zapper-zap.com/ Thank you.