dansciurus,
If you do a search on 'A2' here on cpf, you will bring up many pages of threads. While the incandescent bulb is protected by being overdriven by 2xCR123a cells, the leds are not, and some people worry about harming the leds - however, if you get Koala's "onion" rings, the leds will be protected. Calipsoii's led rings may be protected too, but I am not personally familiar with that product. I have listed links to both aftermarket led rings below, and they are of different designs. If you have a ring that protects the leds, the general consensus seems to be that the best rechargeable cell to use is the AW IMR 16340 (red). If you can get ahold of the much-sought-after discontinued Fivemega A2 "strion" socket adapter, you can use much less costly Streamlight Strion bulbs, or the Streamlight Stinger bulb for a longer bulb life, but yellower beam. If you can't get a FM socket, the Lumens Factory bulb for the A2 is probably just as good, if not better, than the original SF bulb, which is pricey.
http://www.candlepowerforums.com/vb/showthread.php?288701-FS-Onion-Rings-(SF-A2-LED-rings)
One of the great things about Koala's rings is that you can put in any 5mm led you want (once you've properly prepared the leads), including warm white, red, or UV, for example.
[edit: unfortunately, Calipsoii seems to not be making rings at this time]
Now that Calipsoii has, at least for now, ended his production, I wish I had bought one... Here is the link to his closed thread:
http://www.candlepowerforums.com/vb...urefire-A2-Aviator-LED-rings-(2nd-Run)-*OPEN*
If I could get a Calipsoii ring and a Fivemega socket, I would probably consider getting another A2. I already have a couple of Koala and FM outfitted A2 lights, and they are keepers.
