If you ordered Apple’s smart battery case for your shiny new iPhone 7, you’re in for a neat surprise. The iPhone 7 version of the case comes with a battery that is 26 percent larger than the iPhone 6S edition, with a bump from 1,877 mAh to 2,365 mAh.
Given that the iPhone 7 has a 1,960 mAh battery, I’d guess Apple wanted the battery case to actually be able to fully charge your iPhone, and it added in a little extra juice for fun. Apple says the smart battery case combined with your fully charged iPhone can give you 22 hours of internet use over LTE or 26 hours of talk time, which is enough juice to get even the most ardent user through an entire day.
Source: The Verge