Muiltifunctional can be used as MP3 FM radio voice recorder card reader. With TF card slot. Button function: Switch on/off/play/pause/automatic searching. On a radio/song/a volume reduction (long press). The next song/next station/volume plus (long press). Recording/playback. FM/MP3 mode conversion. Indicator. TF card slot. Charging/data interface. Earbuds. Charging: connect the USB cable to devices and the computer or with USB interface DC power plug(5V). Red light when USB cable connect with the devices. Blue light when charging full. Working state when the battery voltage is too low will be bright red light the machine will automatically shut down please recharge in time. Can stretch 3cm.