[Product material] plastic+electronic parts[Single product weight] 104GPlay: Gyro transmitter clockwise three times， rapidly rotating， issued by the colorful light， there are pop songs. Very nice (usually sliding tens of seconds).Battery Replacement: 3 gyro built on the 7th battery. Battery dies you can use a small screwdriver tool to unscrew the gyro top of the screw， remove the battery rack to replace the battery， as is for a good recovery can be.Principle: the gyroscope or spinning top is a toy， the ancient name of thousands. It can rotate around the central axis， the balance in the gyro state-of-the-art.