SureFire 6-Pack Premium 123A Batteries Lithium SF123A
I've used these exclusively for about ten years on optics, weapon lights, etc. I have used Energizer and Duracell as well, good stuff too, but not on anything I rely on other than a surefire hand held light.<br /><br />Most of these top brands use the same cells, as do a few no names. Just be sure where they're getting them and how they are being assembled into the battery itself. If you don't know for sure, buy Surefire.