1.Built-in lithium battery 2.CE,ROSH,FCC approved 3.Professional ... frequency.7.Support various MP3 music files8.Support TF memory card9.Built-in FM FM radio, listenning to ... PC, CD, notebook computers.11.High capacity lithium-ion battery can be repeated charging.12.Neutral packing13.It contains ... Signal to noise: > 80 dB5.Speaker impedance: 4 OZU6.Battery specification: 3.7 V / 600 MAH7.Charge voltage: ...