... FM frequency TF card,USB,AUX Decoder Board with FM radioStrang decoder: TF card,USB,AUX MP3 Decoder Board, pcb board &ABS board, fm radio and digital screen display, with ... , Car audio, multimedia speaker, subwoofer, amplifier, electronic ... USB→SD→AUX→FM→USB; When only with USB flash drive, it has the switching order as USB→AUX→FM→USB; When only with SD card, it has such switching order as SD→AUX→FM→SD ...