Tarot is the smallest of Powerocks’ battery packs. It’s just as wide as a credit card, and only a little taller, with a thickness equivalent to roughly 10 cards stacked atop one another. The top and bottom panels are aluminum, while the outer edge is a continuous piece of white plastic. In addition to the full- and Micro-USB ports, there’s a power button on top, and four battery indicator lights; all in all, it’s really quite…