No matter how popular smartphones and tablets become, there are two unavoidable problems that most users will run into: limited storage space and limited battery life. The Imation Link Power Drive (16GB) ($99.99) is a flash drive and battery backup device that addresses both of these issues for anyone with a current Apple iPhone or Apple iPad by combining a portable power with storage, all connected through Apple's Lightning connector.

Design and Features
The Link Power Drive combines portable storage with mobile power, merging a 3000 mAh backup battery for iPhone and iPad with a 16GB flash drive. The small, boxy device measures 0.87 by 2.9 by 2.5 inches (HWD) and weighs 3.9 ounces, making it a bit too large to simply carry in the same pocket as your keys, but small enough to slip into a coat pocket or a smaller outside pocket on a bag. A switch on the back of the drive turns the battery off and on, and a button on top doubles as an indicator for battery capacity.

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Built into the drive housing are two
cables: a USB 2.0 cable for connecting to a PC, and a Lightning cable for plugging into iPads and iPhones. Cable storage is also built into the device, with a channel for the cables and slots for the connectors running around the circumference of the device. Neither one is particularly long. The USB cable is a short 2 inches, while the Lightning cable is 5.3 inches. On the bottom of the drive is a sliding tray that serves as a stand for your iPhone, letting you prop it up to watch a movie while it's plugged in and charging.

The Link Power Drive comes preformatted to FAT32, making it compatible with both Windows (8/7/Vista/XP) and Mac (OS X 10.7 and higher) systems. The Lightning connector, on the other hand, makes the mobile storage and battery charging compatible only with iOS products (iPhone, iPod, and iPad, all fifth generation or later). Android users might consider something like the Kingston DataTraveler microDuo 3.0 (64GB) for extra storage on tablets and phones.

Software
There's no software preinstalled on the drive, but there are some default folders: Contacts, Documents, Music, Photos, and Videos. In order to access your files on your iPad or iPhone, you'll need to download Imation's free Link Power Drive app, which is available through iTunes. The app gives you central access to the contents of the drive, with access to your folders and media, as well as local storage and contacts.

File transfers to and from the Link Power Drive are simple enough, even letting you copy Word documents and PDFs onto the phone, and transfer files from either your computer or your phone easily. It supports several media file types (MP3, M4A, MP4, MOV, BMP, GIF, JPG, PNG, TIFF), and any media on the drive can be played back on the phone through the app, without having to transfer anything first. Finally, the app also lets you back up your contact list and camera roll to the drive, making it a little less nerve-wracking to lose your phone.

Pricing and Performance
The one thing the Link Power Drive is not is cheap. Our review unit offers only 16GB of storage, but has a list price of $99.99, which is roughly $6.24 per gigabyte. The larger capacities are slightly better: A 32GB model ($129.99) comes to $4.06 per gigabyte, and the 64GB model ($149.99) is the most affordable at $2.34 per gigabyte. The price obviously is for more than storage—it's also a pretty good battery backup, but unlike the uNu Superpak or the myCharge Energy Shot, you get storage in the mix as well.

Unfortunately, when it comes to iOS compatible storage, other options aren't much better—the PhotoFast i-FlashDrive (16GB) is an even steeper $10.62 per GB. If you're just looking for storage, you'll do better with something like the SanDisk Connect Wireless Flash Drive which offers swappable microSD card storage and wirelessly connects to all sorts of mobile devices, not just Apple products.

Don't count on the Link Power Drive for speedy performance, though. It'll do the job for watching your media, but everything else will be noticeably slow. When I tested the average read and write speeds in our timed data transfer test, the the Link Power Drive averaged 11 MBps (read) and 9 MBps (write). By comparison, the iPhone-compatible PhotoFast i-FlashDrive averaged 32 MBps (read) and 4 MBps (write) in our tests. Compare this with the Android-only Kingston DataTraveler microDuo 3.0 (64GB) which averaged write speeds of 38MBps and read speeds of 12MBps, and the differences aren't so large.

Conclusion
There are some weak points to the Imation Link Power Drive, like slow performance and a high price per gigabyte, but these problems are endemic to Apple-specific storage products. Setting aside those two concerns, the Link Power Drive isn't bad, offering both storage and power whenever you need it most. For most mobile storage needs, I'd recommend something like the Editors' Choice Kingston DataTraveler microDuo 3.0 (64GB), but for Apple users, the Imation Link Power Drive is a handy device to have.