This is built around the Chronos Ez430 RF Development kit.
This basically is a 868MHz/915MHz RF band link with the CC430 based watch. The USB dongle provided in the kit is used as the receiver on the PC side. The Accelerometer built into the watch is used to detect the movement by the Hand and then transmitted over to the PC to detect it as a Mouse move operation. This can be of great help during presentations and demos.This also is a great gaming joystick, watch its video to find more.
In all a great innovative and efficient use of the Wireless and Accelerometer technologies.
I was once planning to have one of these, but now I have some more justification to buy one.