parazapper
I am a manufacturer of zappers and have been since 2000. After having designed and tried many types of zappers, I find that the sweep zappers do not do as well as expected.
The reason is that they do not maintain any one frequency long enough to be truly effective.
We provide a lot of information about zappers and zapping at
zapper from paradevices.com where the only thing sold is a booklet about "
parasite Zapping and the Zapper" which explains many aspects of zapping and zappers, what to do, what not to do, how to get the best results, etc.
We also have several models of quality zappers available at another site.