I have a bunch of empty Tic Tac containers sitting around and I've been dying to find uses for them. Today the lightbulb came on: CR123 AA AAA Three CR123s fit nice and snug. The container bulges very slightly, but that keeps them in place. Three AAs fit like the container was made for holding them. Just a little extra space vertically, but the batteries stay in place. 5 AAAs fit with a bit more bulging than the CR123s, but still not overly so. A 6th could be squeezed in across the top, but it puts pressure on the cap and makes it prone to popping open. 4 AAAs will fit side by side though they rattle around inside. I haven't carried these or really done any testing to see how durable they turn out to be; so far this seems like a good solution for a water/shock resistant battery container especially considering they cost about $1 and you get a handful of free mints ;D *EDIT: I forgot to mention these are the 1 oz "Big Pack" containers.