Your iPhone's battery is running low? Well, that shouldn't be a problem with the new iPad Pro 11" and 12.9" slates, which can charge your iPhone in a jiffy.
Of course, this would only work if you have one of them USB Type-C to Lightning cables lying around. Oh, you missed the news? The new iPads are equipped with USB Type-C ports, hinting that next year's iPhones might also make this important switch.
This is the first time Apple has allowed its tablets to reverse-power other devices, and the reason for that is simple - this feature was "unlocked" by the inclusion of the USB Type-C connectivity standard, which is much more capable that Lightning cables in both data and power throughput.