This product is small and light so will fit into a pocket easy enough. It comes with a handy short microusb cable which charges itself off a AC USB charger or any USB device. This short cable makes it even more portable. Its output of 1A will even charge my Toshiba AT300 which comes with a 2.1A wall charger and will not charge off a standard computer 0.5A USB port, but very slowly. Of course with a 2Ah battery, it cannot be expected to fully charge the AT300, or even my LG 4X HD with an extended 4.1Ah battery. It also get warm when charging my AT300, due to the high drain I think. It will however give a useful boost in an emergency when you just have to make that phone call or send that email.
Now why did I take a star off? It does not have any switch on its body and is turned on and off by plugging the USB cable into the outlet. So you cannot leave the cable in the outlet as I believe it will drain the battery. You can however plug it into the microUSB in port but since microUSB is smaller and therefore weaker, I am not sure if this is a really good idea. As a result of not having any switch, the device communicate with a series of flashes of its LEDs. Good luck remembering what the flashes means. It will be so much better if they can print the information on the body itself.