Dr. Hulda Clark conceived the technology and the original circuit for a device she described as a Zapper . Dr. Clark first published her theory and description of Zapper technology in 1993. Through this experimentation it has been anecdotally reported that frequencies in the 2,000 - 3,000 Hz range may be more effective in certain situations. The Multi-Zap was designed to give you a choice by including two frequency settings in one unit. Bear in mind that if ones desires a zapper that is exactly as described by Dr. Clark than all one must do is use the Multi-Zap in the 30,000 Hz setting.
Many users choose to modify the timing cycle to suit their individual needs .
If an AC adapter were to malfunction it could send high voltage through to the zapper. A nine volt battery power source is much safer. Also, unlike a battery, AC adapters do not produce a pure DC voltage. A certain amount of 60 Hz AC line frequency comes though and this would interfere with the pure pulsed DC Squarewave output of a Zapper. In addition, the battery lasts a long time so we feel there is no need to offer this feature.