I think they are both right! Both zappers work but in different ways. Blood electrification gets rid of bugs in the blood stream but won't touch the gut if that's where they are hiding. You have to hit all the possible areas where the bugs are or the site of infection/infestation. The Hulda Clark frequencies target parasites. I have the Beck and Hulda type zappers and they both work. These days you can buy zappers that have both the Beck and Clark freqs. in one.