Sony MDRXB950BT/B Extra Bass Bluetooth Headphones (Black) Bluetooth audio streaming with AAC and apt-X support, Electronic Bass Boost circuitry for added bass emphasis, Passive mode for normal, corded operation without battery. Connectivity Technology: Wireless Comfortable around-the-ear design, 40mm drivers for wide frequency response (3 - 28 kHz, with cord), Built-in microphone for hands-free phone calling, Rechargeable battery for up to 20 hrs music Convenient One-touch listening technology, Sophisticated swivel design for portability, USB charging cable and detachable audio cable included