Apple has just released its all-new iPhone 11, iPhone 11 Pro and iPhone 11 Pro Max battery cases and unlike any other battery case we've seen the giant Cupertino release for its iPhones, this one includes a novelty— a key which automatically unlocks the shutter.
source ; apple.com

source apple.com
There's certainly no new concept of a camera button on an iPhone case, but this is an official option and it's hard to find a case that extends your battery as well.
What's also curious is that the camera button is positioned at the bottom half of the case (just where you'd have a point-and-shoot shutter release button) and not like a normal button pressing a quick key on the device. Apple-designed this button exclusively for this case, and it's unlikely you'll find it anywhere else. In reality, even when the phone is locked, the key apparently works.
The camera is opened by pressing the button, even if the phone is locked. A click takes a photo and a QuickTake clip is taken by a longer button. Its pretty good.


The cases of the Smart Battery are also compatible with Qi-certified chargers to allow wireless charging. This means you have your iPhone's wireless charging pad, you don't have to remove the battery case and charge it separately. It also supports USB-PD chargers and Lightning accessories like EarPods. We display the state of the battery on the iPhone lock screen and notification center when you add the cases.
For each case Apple is not too precise about the expectations in battery life. Regardless of the device you use, in a non-stop video replay check, the firm vents up to 50 times longer battery life. If you are more interested in other tasks, your experience will probably vary.