... SD card,play mp3 format music 2,with FM radio 3,Built-in rechargeable lithium battery 4,AUX function Name:USB/SD SpeakerSpecification ... intelligently .2,FM radio function(Built-in FM antenna).3,Clock, alarm function.4,Built-in rechargeable lithium battery(Circuit with Charge Management)(charging ... ,AUX function.Standard 3.5mm audio output jack. USB Speaker with FM radio