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In theory, a good battery case should be the only accessory your smartphone needs. When done right, they blend the protection of a standard case with the emergency power of a portable battery. Two birds, one stone.
With something like the iPhone 6, which has neither the toughest design nor the longest lasting battery, they can be particularly helpful.
Most cases, however, have a hard time balancing their priorities. Plopping an extra battery onto your smartphone is inevitably going to add some heft, but lots of battery cases sell out for that extra juice and make the phone overly thick. That may be worth it for those who are constantly on their phone, but most of the time you'll want something that has enough power to get you through the end of the day, yet won't make the thing in your pocket feel like a small brick. If it's affordable, even better.
Anker's Ultra Slim Battery Case is one of the few iPhone 6 cases that gets that mixture right. With a stated capacity of 2,850mAh, the slider case isn't the most powerful around, but it's still strong enough to fully refill an empty battery. It's been certified by Apple to power this specific iPhone, it fits well, and it charges quickly to boot.
The biggest appeal of the Anker Ultra Slim is its slimness; it measures just 0.23 inches thick. It's light, too. It does make the phone a bit taller, but the iPhone 6 is relatively compact in the first place, and that extra space further protects your device from any moments of clumsiness. Add all that to a smooth (if a tad greasy) frame, an 18-month warranty, and rave reviews from both professionals and users alike, and you have a well-rounded investment.
More than anything else, though, the Anker Ultra Slim is a good value. It retails for $40, which is lower than the vast majority of MFi certified cases you'll find on the market. If you want the benefits of a case and portable battery without the clutter of carrying both — and you want to take it easy on your wallet — it's worth a long look.
Anker Ultra Slim Extended Battery Case for iPhone 6 / 6S (Black), $39.99, available at Amazon.
