... 2) 3.7V(500mA/h) 3) FM function 4) Play Music connect other Equipment Portable car mini speaker, outdoor speaker factory outlet The ... main function1.Play the songs of TF card2.Built-in battery,3.7V(500mA/h),Rechargeable ... :DC-5V/USB,LINE INBattery / power supply:Built-in, 3.7V(780mAh)Audio formats:MP3Output power:4wPeak power:4wSensitivity:90dBFrequency ...