Ok, I went for it! Should have it in a week or so! I got the newest XM-L2 U2 emmitter. I'm pretty sure these are rated to take li-ions. The guy I ordered from says that he has only tried them with the eagletac 16340/RCR123A batteries, and they seem to work as they should, without loss of modes! Has anybody tried them with the nitecore batteries?? Do they keep all modes?