For some time already, most iPhone cases either acted as protective or battery packs. No one thought of making it into a storage case. No one except Mophie.

Mophie, the makers of those handy battery pack cases, has unveiled the world's first smartphone case with built-in storage for iPhone 5 and 5S. You can plug your phone into Mophie's 16GB or 32GB space pack to double or triple your iPhone's capacity.

There's also an accompanying app, Space, that makes it easy to manage files, movies, music, photos and more. There's no need to be connected to the data network to access your files.

The pack will go on sale March 14 and will cost you $150 for 16GB and $180 for 32GB.