Wirelessly streams music from Bluetooth-enabled devices NFC technology for instant Bluetooth setup Speakerphone features a built-in microphone, digital voice echo cancellation & answer/end controls Reson8 speaker chamber technology Aux input for audio devices equipped with 3.5mm headphone output 2-in-1 charging via built-in 2,600mAh battery & 2,600mAh removable battery Charges mobile devices via removable pop-out battery pack with USB port Battery level indicators for both internal battery & battery pack Includes 100V-240V universal voltage AC adapter