The T100 runs from a single 123, I believe.
TigerLight was supposed to send me one of these to review, but they didn't, unfortunately. I'm rather short on cash right now, so I'm not going to buy one this month. Thus, unless TigerLight sends me one, I won't review this until at least February. However, I definitely WILL be reviewing it at some point.
I can tell you that from my conversations with Eric and Michael and Randy, that it uses a single 123 and a K2 emiter and has multiple levels via a PWM controller circuit. Plus there are the extra LED's and switch positions mentioned, and, of course, the OC spray (which is why the light looks like a 2 123 setup).
I'm sorry I didn't just buy this light back when it was first available because then I would have a review up by now. But I didn't.
Ah, well, as I said, I will review the light at some point.
As for the series 2 TigerLight, the biggest change is the lack of the gold ring. Other than that it's pretty much identicle to the first series. Some minor things have been changed that needed to be addressed, but it's transparent for most users.