After two weeks of teasing, Sony will finally unveil its mysterious Rolly "audio entertainment device" in Tokyo Monday.

Few precise details of the product are known although the company has been releasing tidbits of information for the last two weeks on a dedicated blog. Among the snippets: Rolly has just one control button and doesn't have a display. Further clues have come from words scrolling across the bottom of a promotional Web site, which include: vivid, move, beauty, imagination, share music, and dance.

Perhaps the biggest insight into the product has come from a leaked video, currently available on YouTube, that apparently shows the device. It appears egg-shaped and has two large rings on which it can roll around the floor. Covers on each end of the device open to reveal speakers when it's switched on and while music is playing it moves around the floor in time to the track.

The original source of the video isn't known although it closely matches a clip on Sony's official Web site, so it appears to have come from the maker.

But even after viewing the video, the exact method of operation isn't clear and a bigger question remains: exactly what is the idea behind Rolly and what's it good for?

Answers to these questions should come on Monday when Sony unveils it to local media and later in the day to 50 customers at a launch event.