Features: 1. Made of high quality wooden base, which is natural and eco-friendly. 2. A science cradle balance ball based on Newton's law. 5 solid ball and fine fish line material, ensure the durability. 3. Swing time: The balance balls continue in perpetual motion for only 15-25 seconds due to the resistance of the air and friction, but it won't influence the effect of playing although it can not reach the seamless convergence among balls in the vacuum. 4. Watching the back and forth movement of the balance ball, gives you a day-to-day soothing experience. 5. Suitable for psychology, teaching tools and furnishings, a nice gift for your kid, let them experience the fun of mechanics in the process of playing this fun gadget. Specification: Condition:100% Brand New Material: Wooden base +5 solid balls + fine fishing line+Metal Bracket Color: As Pictures Shown Size: approx.14*11.5*15cm/5.5*4.5*5.9in Weight: Approx.519g/18.3oz Package list: 1 * Newton Pendulum Ball Note: 1. Please allow 0~1 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. Package List 1Made of high quality wooden base, which is natural and eco-friendly 2A science cradle balance ball based on Newton's law. 5 solid ball and fine fish line material, ensure the durability 3Swing time: The balance balls continue in perpetual motion for only 15-25 seconds due to the resistance of the air and friction, but it won't influence the effect of playing although it can not reach the seamless convergence among balls in the vacuum 4Watching the back and forth movement of the balance ball, gives you a day-to-day soothing experience 5Suitable for psychology, teaching tools and furnishings, a nice gift for your kid, let them experience the fun of mechanics in the process of playing this fun gadget