Sony has unveiled what it claims is the world's lightest netbook, which weighs in at just 638g.

The new Vaio P Series measures 120mm x 245mm x 19.8mm, making it about the size of a business envelope and roughly as thin as a mobile phone. It sports an 8in X-Black 1600x768 screen that utilises Sony's Xbrite-Eco LCD technology.

The device, which was shown off at this week's CES event in Las Vegas, also boasts an Intel Atom processor, 2GB of RAM and a 60GB hard drive. The range includes a model featuring a 128GB SSD instead of a conventional hard drive, further reducing the weight to 618g.

Other features include mobile broadband, 802.11n Wi-Fi, Bluetooth and GPS technologies with pre-installed maps for the US and Canada.

According to Sony, users should get about four hours of use out of a single charge from the standard three-cell battery and about double that when using the optional six-cell high-capacity battery.

The Vaio P Series will also give users the option of booting into Windows Vista or quickly accessing media features such as instant messaging, internet and music from the XrossMediaBar interface.

"The Vaio P Series Lifestyle PC is your portal to the world, delivering entertainment and computing in a head-turning device that's small enough to put in your pocket," said Mike Abary, senior vice president of Vaio product marketing at Sony Electronics.

The Vaio P Series Lifestyle PC will be available from February in red, dark green, black and white, and is expected to retail for about $900 in the US and from £849 in the UK.