The Plantronics Discovery 640 Bluetooth Cell Phone Headset lets you stay connected like never before. This device features a sleek in-ear design and an innovative pocket charger that gives you up to 15 hours of talk time. The unit's charger is powered by a single AA battery. The Discovery 640 weighs in at only nine grams and it is stylish, comfortable, and convenient. Plantronics combines cutting-edge technology to set a new standard in Bluetooth wireless headsets.