Hi Sarah there are quite a number of zappers on the market now in the US. At least one company in the UK which I will tell you about.
I got hold of a Multizap from Essence Instruments from the US with 2 frequencies 2.5k and 30K (H.Clark's preferred frequency) pretty neat I thought, but may not have been necessary. Clark says 30K eliminates most of the parasites anyway. My reservation with this model has always been the thin cable type leads it comes supplied with with pins on the end. Eventually one lead broke off where it joins with it's pin -18 months later!
No complaints really, but leads are too thin and easily pulled and damaged. The pins are then fed into rubber wrist pads.
(I have managed to replace those leads)
In the UK I picked up a Becks zapper -an entirely different device in the way it operates and can eliminate all kinds of micro-organisms in the blood. This only happens if your immune system is severely compromised. If this is the case you will know it well! I got my Becks zapper from Commercial Science (UK) see website below who also produce around 4 models of the Clark's type zappers -which are the kind you are enquiring about. The better zappers are 14 volts -as opposed to 9 Volts in the Standard zapper. Zappers start at around $40 in US
or £40 in UK (!) You may be liable to customs charges if bringing it in from the US -but not always!
These higher voltage zappers should have deeper penetration but I haven't tested them myself.
Terminator II is one of the best zappers for penetration I hear. There are several sites in the US that have Terminator for sale.
Price is around $100 and you will have to send off for it.
I'm not sure what accesories are included with Terminator 2.
Best find out!
Hope to have been of help.