... inside,phone call recoreder,super stereo bass round,wireless to mobile phone. Specification * Bluetooth Version, V2.0* Talking time,15 Hours* ... <0.1%*Frequency response: 20-20,000Hz*Output power: 20mW (Bluetooth)*Playing time: 8-10 hours*Battery: built-in rechargeable Li ... -ion battery*Standby time (Bluetooth): ≥ 200 hours*Charging time: about 2.5 hours*Port: ...