External USB hard drives provide a quick and easy way to add storage space to a computer without the need to ferret around in the case, with the added bonus that they're easy to move from one computer to another.

But the inherent problem with removable storage is that it can be far more easily lost or stolen than an internal hard drive. Losing data is bad enough – especially if you've misplaced photos or precious documents – but its potential use if it fell into the wrong hands hardly bears thinking about.

At about the size of two packs of playing cards, the DiskGenie is a portable hard drive with a difference. The slightly rubberised casing features a number pad, which you use to enter a PIN in order to access the files within.

256-bit AES encryption is built in, and requires no additional software. Pressing a combination of keys puts the device in admin mode, enabling you to change the default PIN.

Once this is set, any files stored on the drive are inaccessible until the PIN is provided again.

Security at a price

The integrated USB cable means that there are no worries about establishing a connection to any computer. This cable is fairly short, but the drive is also supplied with a double USB cable that you can use as an extension.

The double cable also helps to overcome the problem of a USB port supplying insufficient power for the device, as you can plug the drive into two USB ports simultaneously to boost the power level.

The drive is supplied NTFS formatted, ready for use with Windows, but instructions are provided to help you configure it for use with a Mac or Linux system.

Of course, there's a catch: there's no getting away from the fact that the DiskGenie is expensive. External hard drives of the same capacity or even higher are available for less. We agree that the ability to protect valuable data is hugely advantageous, but here it certainly comes at a premium.

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