I have still heard no sensable reason why any one zapper is better then another, Hulda Clark said that any frequency betweem 10Hz and 500,000Hz is equally effective against parasites.(pg 15) I think we need to remember that there is really no differance between zappers. (make sure yours is not a specail case, there really might be a few spoofs out there!) The best zapper I've ever heard of and used is http://zapperplans.com/ it's a durable, highly efficiant, down to earth, good service received and $10 zapper. Works great. Also zappers are extreemly easy to build at home http://zapperplans.com/ http://sbherbalremedies.com/books/the_cure_for_all_diseases.html
and they are just as effective as the others. They'll last a long time if you build them sturdy enough too.