Re: Which zapper???

> No, it uses an entire different type of chip and different components.

Well the output is the same, but it's true that the components are different. They conserve more power with the CMOS inverter chip than the 555 timer would, so I think that's a good feature.

The idea of special frequencies being better is not from Hulda Clark , I do not know if they help or not. I have successfully lowered the frequency on a $10 unit by soldering in a different capacitor.

It ships with plain copper finger-rings, which may not be as effective as the large paddles. (Again nothing from Hulda Clark on this.) The alligator clips on the $10 unit could easily be attached to larger paddles.