The boombox comes with an ac cord to plug it into a wall socket. You use it to charge the built-in internal rechargeable battery. The hours of airplay you get on a full charge will depend on how it is being used: the loudness setting for the speakers, whether you are using bluetooth, whether you are playing or recording with the cassette player/recorder. With the speakers set to moderate volume for a small room and playing the radio I have run the radio for 10 hours with no problem.