Kingston has announced availability of the Wi-Drive. This product addresses an annoying limitation of the Apple iPhone and iPad: no USB port for external storage devices.

The Wi-Drive overcomes this by connecting wirelessly. It offers 16GB or 32GB of solid-state storage, with USB for charging and for access to the files from a PC or Mac. When you are on the go, you can put the Wi-Drive into your pocket. A free app on the iPhone, iPad or iTouch lets you access the files. The use of a network bridging means you can still access the internet. Battery life is said to be up to 4 hours, so I hope you can switch it off when not needed. You can also share the drive with up to three other users.

Example prices are £89.99 for the 16GB or £124.98 for the 32GB version.

It is a clever solution. That said, I have a couple of reservations. One is that the price is high compared to a simple USB device of the same capacity. That is not unreasonable given the extra technology needed, but it means it will only sell to users who really need it.

And do you need it? If you are on the internet, you could use a file synchronization service like Dropbox, or Apple’s own iDisk or forthcoming iCloud, to extend storage instead.

A second problem is that iOS does not expose its file system to the user. This means that external storage is less convenient on iOS than on other systems. Want to save a Pages document from iOS to the Wi-Drive? You probably cannot do so directly; there is no way to save direction to Dropbox either.

The Wi-Drive only exists because of Apple’s desire to control and supposedly simplify the operating system. It is a workaround, but not a perfect one, although that is not the fault of Kingston.

That said, I have not yet tried a Wi-Drive; I hope to bring you a proper review in due course.