The Sony Ericsson Bluetooth Watch, the MBW-100 was made for the purpose of receiving bluetooth data from your cell-phone and displaying it on your wrist. The OLED screen will display a caller ID, and allows the user to accept or reject the call. It can also notify you of a new text message, and also can control your cell-phones music by allowing you to play, pause, and skip songs. Unfortunately it was only made to be compatible with certain Sony Ericsson phones.
Links to Sony Ericsson Bluetooth MBW-100 Watch:
Sony Ericsson Bluetooth Watch [Sony]
Sony Ericsson MBW-100 Bluetooth Watch Shows Who’s Calling [Mobiledia]
Sony Ericsson Bluetooth Watch [Gizmodo]
Sony Ericsson’s MBW-100 Bluetooth watch reviewed [Engadget]