... /Pau,repeat,mode Decoder Board with FM radio for SD card,usbFunction and features: SD/MMC/USB Card MP3 Decoder Board, pcb ... -Application: Ordinary audio combination, Car audio, multimedia speaker, subwoofer, amplifier, electronic products and so on.-Key function: last songs, next ... drive together, it has such switching order as USB→SD→FM→USB; When only with USB flash drive, it has the switching order ...