This power bank by Ventev is unique for two reasons. One, it has a built-in Lightning cable to charge your iPhone, which is a fairly-rare-yet-not-totally-unheard-of feature. And two, it also has foldable AC prongs built directly into it, so you can plug the power bank directly into the wall to recharge it. It’s super convenient — one less charging cable to worry about — and it’s actually pretty rare to find in a power bank.
That said, it isn’t totally unheard of for a portable power bank to have AC prongs. The RavPower 9000mAh ($40), for example, is larger with more storage capacity than the aforementioned Ventev Powercell 6010+ ($50). Both have an extra USB port so that they’re capable of charging two devices simultaneously. And neither power bank can fast charge your new iPhone. If you like the integrated cable-and-AC-prongs combo, choosing between the two comes down to cost and pocketability.