Ecosol may not have one of the most glamourous devices here at CES, but its Powerstick portable power source is arguably one of the most useful.

Styled like a USB memory stick, the rechargeable Li-Polymer battery in the Powerstick can be fuelled up by plugging it into the USB port of a desktop computer or laptop. Once full, it's ready to rescue any gadget that runs out of juice as you travel - a mobile phone, for example, or an MP3 player.

A small LCD on the Powerstick enables you to see how much charge remains in the device. While we saw the device charge a Blackberry mobile phone, other plug-in adaptors will be produced to make the Powerstick compatible with devices from Motorola, Sony Ericsson, Samsung, Palm, Nokia, LG and Apple.

According to Ecosol's CEO Andrew Kular, the Powerstick is due for launch in the US this year, but no distribution deal has yet been finalised for the European market.

The Powerstick is the first step in Ecosol's portable charging product line. Next, it plans to develop a "self-maintaining energy unit" that incorporates photovoltaic (i.e. solar) cells. This, believe Ecosol, will finally give consumers a truly portable power solution.