– First, the Dual zap is a dual circuit. It is a pulse generator which produces a multiplexed electric signal at a fixed rate. The output is a dual frequency composite square wave. It contains the equivalent of 2 simple zappers, which run on two 9 volts batteries, instead on one. – Second, each circuit generates its own frequency; the two are specially chosen to work together synergistically to obtain the maximum penetration of body organs and of parasites, and give the maximum killing power while being harmless to body tissues.