Item Type: Swing Ball Craft Material: High-Grade ABS Plastic, Fishing Line, Steel Ball Battery Parameters: 4 x AA Batteries (Battery Not Included) Features: Luminous Features: Excellent educational scientific tools, showing the law of conservation of momentum and energy Package List 1 x Swing Ball Craft 1. Please allow 0& 8209;1 inch error due to manual measurement. Thanks for your understanding.2. Monitors are not calibrated same, item color displayed in photos may be showing slightly different from the real object. Please take the real one as standard. 1A very interesting decompression toy, the ball can be used to hit other balls and swing. 2It can visually display the law of conservation of momentum and the law of conservation of energy. 3The perfect educational science tool is also the perfect birthday gift and toy for children. 4Using highgrade plastic and sturdy steel ball materials, it is durable and long lasting. 5It can be luminous, beautiful and exquisite, suitable for home decoration, study room and desk decoration.