The Lambda Nano keychain light is a nifty little device. Too bad they will probably never be made again. There was one last run made. As I type this, there are still some left, but I suspect they will go fast.
This is an impressive little keychain flashlight that will supposedly stay lit for a year before it needs replacing of its SR48 button cells.
Here's the main thread with instructions for replacing the batteries on the Nano keychain light, and here's the BLF thread where I learned about it.
UPDATE: I bought an aluminum green and blue as well before they all get snapped up. Those are the only two left so hurry if you want one!
Below is an animated GIF showing about how it looks in the dark, and you can also see that I now have it attached to my disaster bag.
The aluminum model is a good bit lighter than the brass.
I moved the brass one to my electronics bag and one of the aluminum ones to the disaster bag. Hey, it's something.