09-04-2014, 03:33 PM
I have one of these, and it can be used with one AA battery, or you can add the included extender and run it with two AA's. The extra battery increases the runtime, not the brightness. I've been quite happy with it. Note that the outputs are quite different.
Here are the spec's:

http://www.amazon.com/gp/product/B00DYB9...00?ie=UTF8&psc=1
Here are the spec's:

http://www.amazon.com/gp/product/B00DYB9...00?ie=UTF8&psc=1