If you want to try the Beck Protocol buy a Beck Blood Cleanser. If you want to try the Hulda Clark Method use a Zapper (like Parazapper.
Becks device uses micro Amps of current in the blood to kill pathogens. It should be used with all the other Beck devices for best results. Frequency should be kept low.
The Zapper kills with a positive offset square wave. or pulsed DC.
The problem and confusion comes from people calling the Blood cleanser a Zapper. They are totally different and work using different principals.