People who are on the road constantly are always running out of smartphone juice. A high-capacity USB battery pack eliminates the need to be constantly looking for power outlets for smartphones, tablets, e-readers, and other USB items. They're also pretty small and easy to carry around in your bag for whenever you need them.
We spent over 250 hours researching and testing USB battery packs with a former electrical engineer from NASA, and found that the IntoCircuit Power Castle 11,200 mAh is the USB power bank that most travelers should carry. Little touches like automatically starting to charge devices you plug in without a button press and an LCD that displays the remaining charge by percentage make it feel more thoughtfully designed than the competition.
The IntoCircuit Power Castle can keep a smartphone running for a few days away from an outlet, and it can add hours to the life of a big tablet when you're stuck on a long flight. Portable USB battery packs are a dime a dozen, but this one saves a bit of space, weight, time, and money.