On Tuesday, Apple launched a Smart Battery Case designed specifically for use with the iPhone 6 and 6s, marking the first effort from the iPhone maker to provide an Apple-designed integrated battery pack since it launched the iPhone in 2007.

Apple Smart Battery Case is designed to both protect the iPhone and provide between 18 and 25 hours of extended battery life, depending on use.

Manufactured from soft-touch silicone and lined with microfiber material, the Smart Battery Case holds true to the design of Apple’s existing range of iPhone cases. The battery equipped case features an elastomer hinge to provide the flexibility needed to insert and remove an iPhone.

The bottom of the case houses a Lighting connector and it features a Lighting port via which the case and iPhone can be charged simultaneously and to connect accessories such a Lightning to USB cable or the iPhone Lighting Dock.

With the Smart Battery Case fitted, the battery status is displayed on the iPhone Lock screen and in Notification Center, so users can easily see the remaining charge for both their iPhone and the case.

The design is somewhat untraditional as the battery portion is housed in a small hump on the back of the case rather than a uniform case-back as seen on designs from the likes of Mophie’s Juice Pack. Elsewhere the case includes the usual design elements, including cutouts for the iSight camera, mute switch and headphone jack and slightly raised covers for the sleep/wake button and volume controls.

The Smart Battery Case comes in two colors – white and charcoal gray – and retails for $99. But is it the best integrated battery pack iPhone case out there? Early reviewers have blasted Apple’s Smart Battery Case, suggesting it falls short of what third-party battery-equipped cases offer.

Apple’s Smart Battery Case fails to impress reviewers

An Engadget reviewer “hated” the Smart Battery Case when he first saw it and pointed out that the bump of the back of the case goes against Apple’s signature clean, attractive product design. The Verge criticized the “my-iPhone-ate-my-iPod bump” for its negative impact on design and pointed out that few headphones are compatible with the case, requiring users to use only Apple’s EarPods or use an extension.

Although The Wall Street Journal’s reviewer seemed to like the case, she cautioned: “with a third-party case, you can get twice as much power for half the cost.” She also pointed out the lack of an on/off switch for the case, something third-party cases come equipped with.

In an opinion piece, 9to5Mac’s claims that by introducing an integrated battery case, Apple shows that it is aware of iPhone 6 and 6s battery issues but would rather profit from it than fix the issue by fitting its phones with bigger batteries from the outset.

Various tech pundits blasted Apple’s design choices on Twitter. Here’s a sampling:

Can someone explain to me what is ‘Smart’ about an iPhone case with a hump housing a battery?

— Benjamin Mayo (@bzamayo) December 8, 2015

WHY NOT JUST MAKE THE FUCKING IPHONE TWO MILLIMETRES THICKER IN THE FIRST PLACE https://t.co/Mrd6eqSr6m

— The Hern and the Ivy (@alexhern) December 8, 2015

Images via Apple