It's just a little something I use to store a couple sets of AA batteries in for my flashlight.
Keeps them from rolling around in the bottom of my toolbox and getting all crapy.
I had never seen one before until someone gave me one. I liked it so much that I ordered a few more.
Well cleaning out my toolbox I wondered if anyone else had ever seen one by chance so I posted the photo to see.
Here is some more info on them.http://www.powerpax.net