Not only is Kingston's new DataTraveler microDuo a compact 64GB USB 2 stick, but the other end flips up to reveal a Micro-USB connector that will fit in your phone or tablet. As long as your phone or tablet supports the USB OTG (On-The-Go) standard and USB host mode, you can plug in the microDuo and open, save and copy files straight off your device, and then plug it into your computer with the standard USB port.
Microsoft's Surface is notable for being almost the only tablet with a full-size USB port; most have micro-USB connectors to save space. Kingston has a fairly limited list of compatible devices on its site, mostly Android phones and tablets, but the microDuo also works with Windows 8 tablets that have OTG support, like Dell's Venue Pro 8. Windows Phone doesn't currently have OTG or USB host support and iPhones have their own connector, so the microDuo is of most use to Android and Windows users. Not all Android devices have OTG enabled, however — there's an OTG Checker app in the Google Play store you can use to check before buying.
We tested the microDuo with several Samsung phones and the Venue Pro 8. Accessing and copying files was as simple as it usually is on those devices: Windows Explorer opens automatically to show the files, as does the Android file manager. Copying files to or from a PC using the full size USB port gives you standard USB 2.0 speeds (which makes it much slower than USB 3.0); using the Micro-USB port on the Venue Pro 8, we copied 34MB of files to the microDuo in 4 seconds, which is a respectable 8Mb/s. File copies on Android are a little slower, and the speed varies between devices. You can also play music or videos directly from the microDuo without waiting for the files to copy across (or if you don't have space for them). We didn't notice any latency issues — videos played smoothly and music tracks didn't skip or pause.
If you're not playing files back directly, you won't want to leave the microDuo plugged in for long periods of time. On Android phones especially, we found it became warm to the touch and it will also use up more battery. Also, the thickness of the stick can mean your phone doesn't lie flat on a table when you have it connected. As it's so small, it's worth digging the lanyard out of the packaging and hooking it through the loop on the side so you can clip it onto something. It's certainly small enough to mislay.
At £30 for 64GB, the microDuo is only slightly pricier than a standard USB stick, and lets you get files off your device far more easily (and far more quickly than emailing or transferring them over wi-fi). Yes, you can always plug a phone or tablet into a PC with a cable to transfer files, but you have to have both devices with you at the same time. You can also access files straight from the microDuo, although that will use up your battery a little faster. The microDuo has enough capacity to use as your regular memory stick; it just works with a lot more devices than usual.