Features:
* Support Bluetooth/Line in Audio connection, FM radio, TF card, Hards-free calling
* Support L2CAP/A2DP(AVCTP/AVDTP/AVRCP), HSP/HFP
* Voice guidance
* Built-in mic
* Built-in Rechargeable and Detachable li-ion Battery
* 4 Keys operation
  1).Mode key(switch to bluetooth/USB/TF card/FM radio/Line in Audio)
  2).Last song/turn down volume when press long
  3).Next song/turn up volume when press long
  4).Make a call in phone, the pause/play press twice to switch the call to speaker.
       Press once to answer a call. Press long to cancel pairing under Bluetooth mode.
       Press short to search station under FM radio mode.