... ,vol,Pla/Pau,repeat,mode Decoder Board with FM radio for SD card,usbFunction and features: SD/MMC/USB Card MP3 ... .“MODE”: When this player works with SD card and USB flash drive together, it has such switching order as USB→SD ... →FM→USB; When only with USB flash drive, it has the switching order as USB→FM→USB ... when you press this button. Decoder Board with FM radio for SD card,usb