[model kit contains a self]-drawing bow that brings an interactive and dynamic aspect to building this model. The gear transmission system that powers the bow doesn't require batteries -- simply wind up the spring-key on the cello's back, and it'll play a pleasant tune for your enjoyment. [Automated Playing Mechanism]Experience realistic string enchantment as this 3D wooden puzzle is equipped with a gear transmission Organic Core Driven Will play the song Spirited [ Choice] this cello puzzle kit makes for an for birthdays, anniversaries, or any occasion worth celebrating. The package includes every required tool including a step-by-step manual, pre-cut wooden sheets, a music movement module [Impressive Desk Decor]This educational and entertaining cello puzzle serves as a remarkable desk accessory for homes and offices alike. It not only offers a fun building experience but also creates a special scene that arouses the interests of builders and collectors, making it an item they would be proud to exhibit. Colour:As Shown Material:wood Package Contents: 1 x diy material kit 1 x English manual Only the above package content, other products are not included. Note: Light reflection 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.