Music Box is motored by remontoir,not need the battery; The Principle of the Music Box is release of the spring in with remontoir, turn the and drive the Sound cylinder. Many bumps on the Sound cylinder, and then it will play the wonderful music ringtone when turning. This is an exquisite gift for yourself or a friend, I hope this music box can bring you happiness and I hope you enjoy the music life. The beautiful melody is very suitable to create a good atmosphere at a party or before going to bed. Music can make you relax and rest, and meditation is the best choice. Name: Music Box Keychain Music: Castle in the Sky colour: silver Material: acrylic + metal size: 5x33x15cm Package Contents: 1 X Music Box Keychain Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.