Okay, I'll admit it...the more I read the less I know and I always end up taking the easy route and just ask! I have a Surefire 6P that I have upgraded with an aftermarket Malkoff emitter and switched to a Keeppower 16650 2500 mAh charged with a XTAR ANT-MC1 Plus. I also have a stock Eagtac D25C2 Clicky that I use standard Surefire CR123's with. I was gifted quite a few of those batteries but they're getting past their "best by" date and I'll probably use them up and just keep a few around as back-up primaries for both lights. My first dummie question is if I want to go to a rechargeable in the Eagtac(which will handle 3.7V fine), is that same 16650 cell compatible? Second dummie question is if answer to DQ#1 is no, what cell could I use that I could still charge on the ANT? Thanks in advance... I know that ignorance, unlikely stupidity, is curable but I'm getting to be a "longbeard" and probably don't have sufficient time left nor the patience!