Most any zapper works...

Most any of them work just fine--the trick is more about how long and how you place them. While Dr. Clark felt it killed all the parasites to zap anywhere on your body, I always felt better about keeping the infestation site in the 'flow', so to speak. Dr. Clark thought if you did right hand to left foot and the left hand to right foot, you'd catch pretty much all the little buggers. I did that but then I'd run some thru whatever area I thought was infested, like side to side thru the torso for stuff in the organs.
But the key here really is to be persistent---the cancer took a couple hours a DAY for the better part of 4 months to wack. And in her later books, even Dr. Clark thought just zapping for an hour straight with out all the hooha of the 7 min on/20 mins off stuff worked just fine. Way back when I started, I did do it that way, but I found it was a lot quicker to not have to fuss with all that. If you have a lot of parasites, you'll want to start with less time and not dump all those carcusses on your poor body all at once--had my ex start out 3 to 4 mins and work up from there, but if you've done some killing of the parasites before, it shouldn't be as bad as his was.
But if you do end up zapping too much at first, it won't hurt you, it'll just give you some flu-like symptoms, which will be a good indicator to cut back a little. Oh, and make sure to replenish your good bacteria with a supplement, or I've heard the live culture yogurt works pretty good too (I hate it so I can't say I ever tried it.)
Btw, do you have Dr. Clark's book "Cure for all diseases'? She has a lot of good info about stuff in there, like what toxin and which parasite is the culprit in each 'disease'.