THIS BOSE A20 WAS A BACKUP HEADSET AND WAS NEVER USED OR WORN. IT HAS A SINGLE PLUG, NO BLUE TOOTH, AND COMES IN THE ORIGINAL BOX WITH CASE. DOUBLE A BATTERIES INCLUDED. RECENT UPGRADE TO THE BOSE A30 IS THE REASON FOR SELLING. IT'S BEEN STORED FOR ONE YEAR IN AN AIR-CONDITIONED ROOM.