I got this at the till while buy­ing socks in San Ma­teo for 5 dol­lars.

What is it?

A small prism with a male fold­able USB sock­et on one end, a fe­male USB sock­et, a bat­tery in the mid­dle, a tiny but­ton and tiny led.

How does it work?

When you are plug­ging stuff to charge via US­B, you plug this in the mid­dle, so com­put­er -> back­up bat­tery -> gad­get. That charges the gad­get and the back­up bat­tery. Then you throw it in your pock­et/bag when you leave home.

What does it do?

It lets you recharge rough­ly half a phone's full charge, when you in­evitably run out of bat­tery, so un­less you for­get to charge both things, you'll man­age to sur­vive.

What could be better?

It could come with a mi­cro-usb male in­stead of a USB fe­male, be­cause that means you al­so have to car­ry a ca­ble (no big deal)

What does the button do?

It stop­s/s­tarts the cur­rent flow in­to the gad­get.

What does the LED do?

Tells you if cur­rent is flow­ing (green) or if it's charg­ing (red).

Can you charge anything?

Yes, but 750mAh is enough to keep a Nexus 7 work­ing for about 30 sec­onds ;-) Does a de­cent job on a Kin­dle though!

Are you going to lose it?

Oh yes, the thing is tiny.

Not a bad 5 dol­lar gad­get. How­ev­er, you can find it in Ama­zon for $30 at some places, and that's rob­bery.