If you want auto-off, that really limits your choices. I'd say a Photon would be the best choice. They last a long time on a 2032 or 2x2016's, have an infinite ramping feature which is nice, and if you want, you can program them so they're momentary activation only, so whenever your kids let go of the button, they'll turn off. They're small, light, decently priced, and come with some nice little accessories too. If you're interested in giving them a neck lanyard for them, don't bother with the cheesy ones included in the package. Get a couple of better ones instead for a couple bucks each, and use those. The included ones are basically just heavy thread really, and don't hold up at all.