I do like the Beck machines a lot, particularly the version made by CZ member Parazapper and would recommend that everyone get one.
Parazapper makes high end Hulda Clark Zappers. Totally different than the Beck Blood Pulser. They shouldn't be confused. Two different devices entirely.
The Hulda Clark Zapper is a positive offset square wave that passes through the body with electrodes on both hands and sometimes feet. The positive offset does the killing.
The Beck Blood Pulser Uses a 4 Hz Square Wave Bi-Phasic. Has special electrodes made solely for passing a current through the layers of the skin into (mostly) the Radial Ulnar Arteries in the wrist. The idea is to pass a weak current through the pathogens in the blood. Most of these devices also make Colloidal Silver .