... last/next song,vol,play/pause,mode -LED display R&D, universal mp3 decoder boardSingle Spectrum with balance display, SD ... speaker, subwoofer, amplifier, electronic products and so on.Another typeR&D, Bi-Spectrum with Tuning PotentiometerOEM & ODM ServiceODM & OEM service ... Introduction Founded: 2000Total Staff: 51-100,including around 5 R&D StaffProduct Line: mini Card& USB reader speaker, portable FM ...