evidence: What is a Zapper and why does it work? [...] If the varying voltage becomes NEGATIVE, even momentarily, it supports and maintains their lives! This must be avoided. You cannot take this for granted when you purchase a zapper. The maker must assure you that it has been checked on an oscilloscope and not even 1% negative voltage found… If the voltage is applied in pulses, to produce a "square" wave, it will affect many parasites at once so that the rate of raising and lowering it, called frequency, is not critical. Even though these tiny animals undoubtedly have a "mortal frequency", this rate does not need to be known or used when a square wave of electricity, totally positive, is used (see page 529). [...] "Remember that killing parasites, by itself, as we can do with herbs, removes the HIV virus source, but this does not return immune power. A zapper, on the other hand, not only eliminates parasites; it does so by returning immune power. Each method has its own virtues." The Cure For HIV and AIDS, by Dr. Hulda Regehr Clark, pg. 71