Just how small can a USB 2.0 storage device get? That is not a question we spend too much time asking ourselves here at Pocket-lint Towers.

After all, as long as it is big enough capacity-wise to hold all our data and small enough physically not to cause "is that a USB stick in your trousers or are you just pleased to see me" remarks, who really cares? The answer, it would seem, is TwinMOS.

We last encountered TwinMOS when they sent us an Imperial Stormtrooper helmet from Star Wars and insisted it was an iPod speaker and now they have gone and done it again by delivering what appears to be a plastic price tag instead of a storage device.

At just 42.6mm long, 14.7mm wide and an incredible 2.8mm thick, this is less thumb drive and more half a little pinkie. It is so small and light, 1.5g light to be precise, that you will be as amazed as us to discover it contains 4GB of flash memory storage capacity.

The idea, we are told, is that you can simply pop it into your wallet or purse and forget it is there until you need it. All very well and good, assuming you can find it again when you do. The B1 is destined to get lost a lot. What would have been handy was some kind of faux credit card into which the B1 could slot, and thus be safely stored in said wallet or purse.

Such a case would also have eased out concerns about the B1 lacking any kind of connector cap, and the USB connection being exposed to possible pocket change or key related damage as a result. We say key related because the only practical carrying solution as is, is to hang it off your key ring.

On the subject of the no-cap design, TwinMOS argue that this is, bizarrely, to prevent the stick from getting lost. We assume if and when a cap works loose, and further assuming it was attached to something via that cap. An excuse that doesn’t wash with us, sorry!

Performance wise though, the B1 is good enough. We saw a sustained data transfer rate of 550KB/sec when copying files to and from the little beastie, and it is also ReadyBoost compatible for those of you with Windows Vista looking to add a little zing to your desktop operations courtesy of a 4GB memory boost.

Price when reviewed:

The B1 could be the miniature storage device you have been looking for, but it’s so small you could be doing just that: always looking for it.