Portable batteries: smartphone users, especially those that don't use iPhones or large phablets will definitely realize this problem. I personal have been using this battery for a while, and it has been good. The 2.1A port gives quite the juice for any tablets, and the normal 1A port is more than enough for my phone.
The nice and bad thing about this is the power button. Unless you hit the power button (the mouth) you will not be able to charge, and when you forget, it sucks.
