Sony has given its Rolly digital audio player an overhaul.

The Rolly is an egg-shaped music player with speakers on either end that twist and turn on two large rings that circle its body in time to music.

Those rings are also used to control the device. One ring can be turned to change the volume and the other to change tracks. It can also stand still and play music, or move to a preprogrammed set of instructions that are fed to it through a PC application.

When it was launched in September last year it received a generally positive response for its innovative shape and functions, and typically draws a crowd whenever it's demonstrated. Sony hasn't released detailed sales figures but said that they're "neither too big or too small, about what we expected".

The new SEP-50BT Rolly will be launched in Japan on November 21 and will be available in white, pink or black, the latter only available though the online Sony Style store. Overseas launch plans haven't been fixed yet. Like the previous model it will cost $427 (£272).

The new version can now be controlled over Bluetooth via a mobile phone. A mobile-phone application can be used to turn up and down the volume, change tracks and stop and start the music player by sending the commands over Bluetooth. The original Rolly included Bluetooth but such control wasn't enabled over the link.

Sony said it is planning to release a software update in early December that will add Bluetooth control to the earlier model.

The new version of the Sony Rolly can be controlled over Bluetooth using a m obile phone