R&D,mp3 decoder board -Single Spectrum balance display -SD &USB,FM radio -last/next song,vol,play/pause,mode -LED ... Spectrum with balance display, SD Card, USB, FM RadioFeature & function: Single Spectrum with balance display, support USB/SD, MP3, FM radio, remote control ... 100,including around 5 R&D StaffProduct Line: mini Card& USB reader speaker, portable FM radio speaker, mobile speaker, active ...