Specification  Model Number: K1  Bluetooth version: V4.1  Profile support: HSP/HFP/A2DP/AVRCP  Transmission distance: 10 meters(depend on the environment)  Built-in rechargeable battery: 60mAh(each),Website:http://www.amicooshop.com,120mAh(Total)  Charging time: About 1.5 hours(one battery)  Talking time: About 5 hours(one battery)  Music time: About 4 hours(one battery)Packing  Packing list: 1* Bluetooth headphone  1* USB charging cable  1* Detachable battery  1* Earhook  1* Earbud  1* User Manual