I ordered one $10 zapper at zapperplans.com and got it fast, and it worked. I gave it to a friend in need, and ordered another. It arrived over 6 months later, with no reply to emails. When I hooked it up to a frequency counter and oscilloscope, there was no output. My second $10 zapper did not work, so I just forgot about it all, and ordered from HuldaClark.com instead. As with all things in life, it seems that you get what you pay for.