The FM Wristwatch Radio was an LCD digital watch with a built-in FM radio. It was Sinclair's second attempt at a wrist radio - the first was the Transrista of 1964 (actually a Micro-6 with a nylon strap).

The watch used a cunning bellows-type arrangement that enabled the chunky face to be broken into three sections which hinged where they joined, so they could make some attempt at bending around your wrist. At the top was the tuner, the middle section was the speaker and volume control, and the bottom was the watch itself, with light, mode and function buttons and the on/off dial for the radio. The aerial was built into the strap - so as long as you stood perfectly still with your arm pointed up in the air you could listen to Radio 1 for at least 30 seconds before you got tired. The battery was hidden in the clasp, presumably in an attempt to balance out the considerable weight of the watch.

Sinclair officially launched the FM Wristwatch Radio at the Las Vegas Consumer Electronics Show in January 1985. However, although Sinclair had tooled up for mass production of the watch and a small number were produced, the device never went into full production. The financial crisis which was to deliver Sinclair into the arms of Amstrad quickly ended the production run. Perhaps it was just as well, considering the practical problems of actually using the thing. This premature curtailment meant that very few Wristwatch Radios were ever produced, making them one of the rarest of all Sinclair products.

• Info and photos courtesy of Damien Burke