* Built-in li-ion battery and USB memory. *Wireless transmission with full frequency transmission from FM88.1MHz to FM107.9MHz,total 199 frequencies for you set freely. transmitted distance is within 5m. if the frequency of your car audio or home audio is same as the frequency of this unit, your car audio or home audio can play the music which is stored in the USB memory of this unit.no need connecting cable. *compatible with USB1.0/1.1 USB2.0. * Optional memory capacity : supports most models of usb-disks * Plays mp3 files. *output power: 5mW *Built-in li-ion battery. *Multifunctional music player:car audio,home audio,mp3 player,usb disk,etc.so you can enjoy the music in your car,in your home or outdoor. *Accessories: earphone,car charger,home charger,user manual. * Real leather package, multiple colors are available.