... 4.built in lithium battery 5.CE,Rohs new electronic gifts/tf card mini speaker Specifications:Supply Voltage: 5V Circuit Current:500mAOutput ... -20kHzImpedance:8RSignal-to-Noise Ratio:>75dBMaterial:enviroment protective ABSFunction1.portable mini speaker,outdoor wireless speaker2.Support TF usb driver,MP3,MP4 ... If any question,pls feel free to tell us. new electronic gifts/tf card mini speaker