We all know that Anker’s PowerCores are far and away our readers’ favorite USB battery packs. But the 10400 model in particular, at least in my opinion, is the best choice for most people. It holds at least two full phone charges, includes two ports for sharing, and is small enough to fit in just about any pocket. Unless you’re going off the grid for multiple days at a time, that’s right in the Goldilocks zone for most people.