Earbud design, Direct sound into the ear for deep bass and extended frequency response. Long time playback/talk. Multipoint connection. Built-in microphone for hand-free phone calling. CVC noise redution technology. Bluetooth version: V4.1. Bluetooth mode: A2DP/AVRCP/Hand-free / Headset. Wireless frequency: 2402MHz-2408MHz, Frequency: 20Hz_20KHz. Receipt distance: 10 M. Battery capacity: 80mAh.