Vtool: keyed freq generators for $15?

Vtool, when you said "There are good frequency generator's that can be programmed to any set of frequencies, targeting specific pathogens for around $300-$400, and even cheaper ones with "keys", that are like $15 a peice, which are Class 1 Licensed Medical Devices in Germany.", could you please elaborate on the keyed freq generators that are so inexpensive? $15 is less than most plain zapper, I haven't seen any type of freq generator for that price range.

I'm sure others will want to know too. Thanks!