Not only does the Apple smart battery case have an off-putting bulbous design, but at $99, the case is expensive for its paltry 1,877mAh battery capacity ("mAh" means "milliampere hours" and is a measurement of the battery's capacity. The higher the number, the longer the battery life.)
As such, there are plenty of other options to juice up your handset that you may want to consider. Click through to see some of our favorites.
The Juice Pack Wireless battery case charges the phone wirelessly through the case, and it includes a powerful magnet for use with various mounts and stands. Mounts are expected to cost around $40 while the case should cost about $100 during launch.
Anker's 2,850mAh battery case increases your phone's life by 120 percent. Its capacity is slight lower than some of the competition, but it's 2.9-ounce weight makes up for it. And, at $40 (or £30 in the UK and AU$53 in Australia at current conversion rates), that's a pretty good deal.
Trianium's case (which retails for $80 or about £60 and AU$105 converted) sports a 3,100mAh capacity, but still manages to stay slim. In addition to juicing up your phone, the battery case adds a layer of protection with a raised edge around the screen.
Mophie's Juice Pack ($119.95 and £109.95, or about AU$167 converted) is more expensive than Apple's battery case, but it provides way more power. The case sports a 3,300mAh battery, and is charged with a Micro-USB cable.
If you want more protection along with more power, the durable Resurgence Power Case does both. Though it adds more heft to your phone, you'll get that extra peace of mind against everyday bumps and drops.