Amazon has the Apple iPhone XS, XS Max, and XR Smart Battery Case in black for $118.51 each (regularly $129) with Free SHipping for a limited time.

The Apple Smart Battery Case supports Lightning accessories, such as the Ear Pods with Lightning Connector, or the Lightning Digital AV Adapter. It can be charged even faster with USB-PD compatible chargers and provides an additional talk time up to 39 hours, internet use up to 22 hours, and video playback up to 27 hours.