Apple today released new Smart Battery Cases designed for its 2018 iPhone lineup, including the iPhone XS, XS Max, and XR.

Available in black or white, each Smart Battery Case is priced at $129 and is designed to add extra battery life to the iPhone. The cases are similar in design to the past battery case option Apple offered for the iPhone 7, with a bump at the back to house a battery pack.

Each case provides a varying amount of battery life depending on device. The iPhone XS Battery Case , when paired with the iPhone XS, offers up to 33 hours of talk time, up to 21 hours of internet use, and up to 25 hours of video playback.

The iPhone XS Max with the XS Max Smart Battery Case offers up to 37 hours of talk time, up to 20 hours of internet use, and up to 25 hours of video playback.

The iPhone XR with the XR Battery Case offers up to 39 hours of talk time, up to 22 hours of internet use, and up to 27 hours of video playback.

Apple has not offered a Smart Battery Case option for the iPhone since the introduction of the iPhone 7, presumably due to the wireless charging feature in the iPhone 8, iPhone X, iPhone XS, iPhone XS Max, and iPhone XR. There has also never been a battery case for larger iPhones, with prior cases limited to the iPhone 6/6s and iPhone 7.

Rumors in December, however, suggested that a version compatible with Qi-wireless charging was in the works, and Apple's product listings confirm that the new Smart Battery Cases are indeed compatible with Qi-certified wireless chargers.

As with the previous versions of the Smart Battery Case, the new options provide an intelligent battery status on the iPhone's Lock screen and in Notification Center so you're aware of the remaining charge of the device.

The cases charge wirelessly as mentioned above or via Lightning and Apple says faster charging is available using USB-PD compatible chargers. Lightning accessories, like the EarPods with Lightning Connector, are also compatible.