 To change the battery, pull on the raised lip to swing the battery compartment open sideways. Turn the audio processor upside down to let the old battery fall out. Remove the protective film from the new battery. It is recommended to remove the protected film one to two minutes before inserting the battery. This allows the zinc-air battery to charge up completely. Place the new battery in the compartment, with the positive pole facing upwards. Push the battery compartment door until it clicks into place.