Smilism Extra Bass Bluetooth Wireless Headphones w/Microphone - Blue Convenient one-touch listening technology, sophisticated swivel design for portability, USB charging cable and detachable Audio cable included 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. A charge of around 4 hours will enable you to enjoy Approximately 30 Hours3 play time. So you can keep on listening, track after track, mix after mix. 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 hours music