These are great and cheap at a buck each. Cheaper than batteries. They are bright and last a good long time.

We give them out in our kids' party grab bags with a bunch of other goodies. Funny that the kids tend to gravitate towards and play with the lights more than the other stuff.

Our kids have one of these lights and a whistle attached to them when we are camping and hiking. I use them as zipper pulls on packs. I give them to clients for keychain use. I have used these for a couple of years now and haven't had one run out of batteries yet. I used to prefer the Inova ones, but these are just as bright and are much less expensive. My kids have drained an Inova microlight in one night's play.