There's nothing worse than getting an "out of storage space" pop-up on your phone when trying to capture a once-in-a-lifetime moment. And once you're locked into a small-capacity iPhone (I'm looking at you, 16GB owners) there's no easy way to expand the storage space -- unlike with, say, an Android phone with an SD card slot. Sure, you can back up to iCloud Drive or Dropbox, but the cost can add up.
SandDisk's iXpand Memory Case, available only for the iPhone 6 and 6s, offers a novel cure for the storage space blues. It builds extra flash memory right into an iPhone case that connects via the lightning port on the phone. And it works very well, although it's much more expensive than an SD card and isn't as good as many cases I've used.
The iXpand comes in four colors (gray, blue, red and teal) three capacities: a 32GB model for $60 (roughly £45 or AU$80), a 64GB model for $100(£76, AU$133) and a 128GB version for $130 (£98, AU$174). I tested the largest size in teal. An optional 1,900mAH battery, which magnetically latches onto the back of the case, is also available for $40 (£30, AU$53).
You'll need to use SanDisk's well-designed companion app to transfer photos from the phone's internal memory to the case, but fortunately that's an easy process. After the transfer is finished, the app automatically offers the option of deleting images from the iPhone, thus freeing up space. The dashboard for the application organizes all the content stored on the drive and makes it easy to move files back and forth and find the ones you need.