Sota is a ripoff. If you want a BBBE only either one from Bioelectric or SilverSmoke Research. A CC2 Parazapper is $90 less than Sota with less costly shipping too and better. Why you can't use MY Parazapper just like a Beck zapper? It sure would meet the original Kaali & Lyman patent Beck kept talking about. The BBBE does not meet the patent anyway, because it used AC current. It would better to use PULSED DC with 100% positive offset. Frequencies 465, 727, 787 and 880 hertz would do a better job of cleaning the blood. That is according to the "Rife" blood cleansing programs of the frequency generators you mention.
"Beck approved" is a joke. Bioelectric, at least thought past Beck and did pick up, very correctly, the best method is the ankle-to-ankle method.