Toshiba didn't make much of a fuss about its UMPC, claiming the smooth-cornered handheld PC was intended to demo technologies the company develops to potential manufacturer customers. One such technology: fuel cells.

Toshiba didn't want to say what the unit's specification was, but we can say it's capable of running Windows Vista. Its shiny-faced casing contains a multi-way navigator to control the cursor and a couple of keys in place of mouse buttons. Presumably there's a tiny Tosh hard drive in there too.

Closer inspection revealed the UMPC is not itself equipped with a fuel cell. Rather, Toshiba's built a fuel cell unit into which the UMPC docks, just as it might sit in a desktop sync cradle. The fuel cell sleeve neatly matched the width of the handheld, adding just a few millimetres to the unit's thickness and almost three centimetres to the height.

Think of it as the handheld equivalent of an extended battery pack you might use with a laptop.

Toshiba wouldn't say what capacity the fuel cell has - there's a theme developing here, no? - either in terms of its physical fuel storage space or its operational run time.