Sound v4 remote control hold the remote upside down in your hand. With the back facing you locate, the crescent shaped depression and place your left thumb into it. Push the small tab towards the larger tab and press up with your thumb to release the battery tray. You may want to use a pen or blunt object to help you with the tab, with the small tab pushed over push the ridge with your thumb, to reveal the battery tray, remove the battery and dispose of safely install a new cr2032 battery taking care. To put it in the same way, the remote will not work if the battery is reversed. The battery side, marked with a plus side, should be facing the rear side of the remote control, push the tray back into the remote.