We all know about external DVD writers. They use a regular internal drive in an external housing with either a USB or Firewire interface (or both), and the result is that an external CD writer or DVD writer is big and clunky and costs slightly more than an internal drive.

The alternative is a slim notebook drive that comes in a smaller housing, and that carries a larger price premium, but both of these approaches require an external power source. This is fine if you are transferring the drive from one desktop PC to another, but it's a pain in the neck if you are using a laptop on battery power.

Happily, we now have a third option; the Freecom FS-50. This is a notebook DVD writer which is rated at 4x DVD+R, 2.4x DVD+RW, 4x DVD-R, 2x DVD-RW, 8xDVD-ROM, 8x CD-R, 4x CD-RW and 24x CD-ROM (phew). And it uses a USB 2.0 interface with a 2MB data cache and an external power supply.

So far, so conventional, but the drive also contains a Ni-MH rechargeable battery pack, and it has not one but two mini-USB sockets. The idea is that you can use the FS-50 in the regular way on mains power with one USB cable or, once the battery is charged, you can use the pair of supplied USB cables to power the drive. To avoid any possibility of confusion, Freecom has colour-coded the ends of the USB cables.

This is an incredibly neat idea, yet Freecom has managed to make the drive quite tiny. It is 150mm deep, 145mm wide and 20mm tall, which is barely larger than a CD jewel case, and the weight of 434g makes it eminently portable. Added to that the FS-50 is also attractively styled, which is just as well with an asking price close to £200.

While you can run the Freecom drive on any USB-compatible notebook or desktop PC from Windows 98 onwards, you'll need to use a USB 2.0 connection to get decent performance. You can also use a Mac with OS 9.1 or higher.

Freecom includes a software suite of Roxio Easy CD & DVD Creator 6 and Roxio DVDMax for DVD playback, which rounds the package out very satisfactorily.

Although the Freecom FS-50 external DVD writer is a clever device that allows you to burn CDs and DVDs without a mains power socket in sight, it is also quite expensive. Mobile business users should certainly add the FS-50 to their Christmas wish-list, but others may find it hard to justify the asking price.