https://wccftech.com/apple-smart-battery-case-higher-watt-hour-rating/

Apple released the Smart Battery Case for its 2018 iPhone lineup yesterday. If you are wondering how it works, the case contains a built-in battery that can extend the battery timing of iPhones. It can be plugged into the Lightning connector of the device for charging purposes and thankfully, these accessories also support Qi charging.

Design-wise, the new case looks a lot like the one released for the iPhone 6 series, although its hump is a little bigger, probably to accommodate wireless charging components. Although Apple does not mention the battery’s capacity on its website, Wirecutter’s Nick Guy has already received his iPhone XS and iPhone XS Max Smart Battery cases and revealed their battery capacity.