so many zappers.. I want one, but WHICH ONE?

This was on the toolsforhealing.com site... love that price! I hear a lot about zapping, but not a lot of recommendations on which zapper to use. Maybe I just haven't read enough. Could someone help me with their experiences?
Zapper C3i w/wrist straps
Zapper - Zapper
Part # MS-C3i
Sku: 141
$68.00
Suggested Retail Price: $79.95
YOU SAVE $11.95!
Low Cost, High Quality
This is our latest, low-cost Zapper.

It's based on Dr. Clark's original specs and delivers high quality, manual operation for a low price. If you need a Zapper and don't want to spend a bundle on fancy features, you need one for occasional use, or you want a second Zapper, this is an excellent unit that will give years of use.

Small size, small price, high quality, and a solid-state design produced on a world-class assembly-line. Powered by a standard 9 volt battery. Comes complete with cables and wrist-straps (instead of handholds) for easy, hands-free mobility.

Blessings -