It does work, I've heard, but it's you doing the tapping to make it work, which gets pretty tiring, I've also heard.
Sorry I forgot to mention that one. I'm sure, had your budget prevented affording even his basic model, parazapper would have have given you this link himself. I've seen him give it before. I personally don't have it.
It'd probably be better to build your own, I suspect if you're able and save up for a better professional one, considering the zapping requirements. It'd certainly be easier, always a consideration for me. :) I have no idea what your budget is.