The Beck Blood Purifier is often referred to as a Beck zapper. It is basically a zapper with a very limited scope.
While it does not have the range of capabilities that ParaZapper does, it can be very beneficial in attacking the infectious microbes that are in the blood. I do believe that the approximate 4 Hz frequency is a limitation and that the multi-frequency units are better than a single frequency. Now, if they can only tackle the accuracy of the frequencies that could be a major improvement.