jimbeetle - 11:48 pm on Feb 6, 2013 (gmt 0)
The description tallies with a patent filing suggesting it plays sound via "bone-conduction" tech rather than earbuds.
Ten or so years ago a Japanese student came up with a wristwatch cellphone. The speaker part was worn on the outside of the wrist facing toward the bone. You listened by sticking your index finger in your ear and spoke into the microphone worn on the inside of the wrist. Ingenious.