1.This product is not only used for bottle puller but also can play music. 2.When the metal part of the opener connect the top of bottle,this product can play music immediately. 3.And there are three songs inside,the songs will be changed circularly when the metal part connect the top of bottle everytime. 4.The battery box is located on the back of the bottle-puller.It uses three AG10 batteries.If the enery is run out,pls unscrew the three screws on the back of the product and remove the battery cover to replace by the new ones.