... ,ROHS,ISO,FCC,CB 2.USB/TF input, 3.FM radio Teacher waistband USB speaker amplifierNewonline N55-redThis mini ... You could hear amplified volum and enjoy it .2.USB/TF/MMC input : when you want to enjoy music ... , just plug in you USB(TF/MMC) to the amplifier slot and you will ... working time: 8-15 hours Function :louder speaker USB/ TF Card FM Radio MP3 input Song Switch This ...