I am using a rife themed "zapper" at the moment. I have found that using antiparasitic herbal formulas alongside the zapping does help to kill some biiiig things where the herbs alone or the zapping alone cant get in there and do the work. And yes some frequencies do attack the worms better than others. But the way i see it, its a very experimental thing, so i am using a wide variety of zapping technologies to help get the body back on track along with a very broad spectrum antiparasitic herbal blend.
One of my most dramatic experiences this way happen last autumn when I was using the herbs and started zapping through hand holds. The whole upper abdomen suddenly got dislocated to the left as a mass of worms died and detached from the abdomen and started to be sent to the descending colon. 2 - 3 days later I passed whole rope worms a few feet long and big segments of tape.
More recently using a different machine I placed the tens pads right and the ropes kicked like a baby in the womb before they died.
Lower frequency round worm frequencies seem to help with this.