In belated acknowledgement that an iPhone battery is not suitable for heavy duty smartphone use, Apple on Tuesday began selling the first Apple-designed external battery pack.
The iPhone 6S Smart Battery Case comes in white and charcoal gray. It is made entirely of Apple-blather materials: soft microfiber lining, soft elastomer hinge, silky soft-touch silicone exterior.
It looks like one of Apple’s $35 silicone cases with a rectangular hump in the back.
No battery specs are provided, but Apple (AAPL) claims its case will extend talk time on an iPhone 6 or 6S up to eight hours (from 10) on LTE and deliver up to 25 hours on 3G. That would put it nearly in the same class as the 2750 mAH Mophie Juice Pack Air, which sells for $99.95.
At $99, Apple’s case is competitively priced—rare for an Apple product. And it’s got a cool feature third-party cases can’t match: “Intelligent battery status” displayed on the lock screen and in the pull-down notification window.
Apple’s timing—two weeks before Christmas, eight and a half years after the first iPhone—is genius.
Follow Philip Elmer-DeWitt on Twitter at @philiped. Read his Apple (AAPL) coverage at fortune.com/ped or subscribe via his RSS feed.
Make sure to sign up for Data Sheet, Fortune’s daily newsletter about the business of technology.
For more on Apple, check out the following Fortune video:
