I've got 3 units...
First, I got a Team 1 Zapper....it seems to work ok....but has poor instructions and rusts really bad......and it weighs 2.5 million pounds. It's very voltage dependent, not something you take to the track because of this....not only will you not get a good zap, but you will more than likely false peak everyones charger and reset some old guys venitlator down the street....not to mention it took a while to get the unit, with little to no response through email.....and my tech support question was never answered after two emails.
Next I got the Trinity Portable zapper.....this unit is self powered, as it uses a huge NEO magnet to zap. It requires no power source. Its very portable, it's what I always take to the track with me...the main downside is the cost, which is over two grand...
And then I got the Zapper Tempest2000 makes.....VERY nice unit. Its much more portable than the team 1....and it even in a low voltage enviroment, it still gets a good zap in the tests I have done...it still is subject to the false peaking other chargers on the same circuit...the unit also is much more resistant to rust and comes with better instructions (which just got better with some additional info they just added).
As of now, at the shop I use the Thunder RC unit on ALL of my production and team motors.....(I still use the trinity unit at the track)....
Later EddieO