Steelseries HS-00007 Dolby Digital transmitter compatible with the Siberia 800 headset.  Comes with transmitter, Steelseries mini USB -> USB A cable, and used 1000 mAh battery for the Siberia 800 headset.  Headset is not included.
Transmitter works, has just been recently replaced with a newer Steelseries set up.  This was in use daily and does have burn-in on the OLED display ("PC" is the most noticeable burn-in), but all menus can still be accessed, etc.