If you carry a pouched Leatherman tool that has pockets on the sides (like the Charge), you can fit a AAA and probably a AA in one of the side pockets. It wouldn't be a bad idea to insulate the battery if you do this. I used to have an ARC-P flashlight in one pocket and a spare AAA battery in the other. Right now I'm carrying the Charge with the belt clip though. I also just received my Doug Ritter Photon and it's already clear that it'll be my new EDC light. Plus it's so small that I'm considering simply carrying two of them and forgetting about carrying spare batteries. I still think the ARC is a fantastic light though.