We were all set to give this little portable hard disk a glowing review. It's tiny, has a cute black rubbery finish and it's cheap. Unfortunately, it also has a fatal flaw.

The reason the Freecom Mobile Drive XXS is so small is that it's basically just a bare hard disk wrapped in a slightly kinky, velvety rubber sheath. And unlike any other drive we've seen before, there's not even any space taken up by an interface to convert a hard disk's SATA connection to USB.

Instead, this is a special Samsung hard disk where the circuitry for the bridge is built into the drive; it doesn't have a SATA connector, just a mini-USB port. Essentially, this is little bigger than a bare 2.5-inch hard disk. Just the millimetres-thick rubber case protects the drive, giving it very small overall dimensions.

Lacking rigidity

The problem is, because the case has no rigidity, the delicate drive internals are afforded very little protection.

This is unlikely to be a problem when you're carrying it around and it isn't plugged into your computer, but when it's in use and the read/write heads are flicking nanometers above the disk platters, slight pressure on the wrong part of the top surface – even from not picking it up by the edges – was enough in our testing to produce a heart-stopping crunch, presumably caused by the heads hitting the platters. This action can shear off the data-holding platter surface, so it's a real cause for concern.

If you're careful with this drive and how you handle it, you could be perfectly happy with it. Even after hours of continuous use, it was still cool to the touch – we'd worried that the rubber would simply insulate the drive and cause it to overheat – and it's tremendous value; even the 320GB model is only £68.

We'd be happier plumping for a drive from Freecom's excellent ToughDrive range, though. They're more robust and we're big fans of the handy captive cable.