... USB,SD,FM function OEM service Magnetically shielded 4.1ch line array speaker with USB/SD/FM radio and VFD 1 ... .Hot 4.1bluetooth speaker , solemn and delicate overlook.2.With USB/SD card read,and FM ... hand, high intensity, effectively eliminate resonance and cabinet noise5. With Standby,Input,Menu,VOL+,VOL- keys on ... sets Hot line array speaker with USB/SD/FM radio and VFD