Dynamic Balance and Energy Conservation: You don't have to worry about it falling off, it can keep balance well. Push the ball lightly and it will rotate 360around the center bracket. It doesn't need any battery, you can rotate it or swing it back andforth.Help You Relax: Its a neat focal point to destress after a busy day at work. When you get bored and feel there is too much pressure, you can put it on your desktop, start it, quietly watching its fascinating swings, it will be fascinating to you. Itcan kill time and help you relieve stressEntertainment Education: This classic desktop game provides you many benefits and entertainments, is suitable for various locations such as house or office, and is an intriguing device that not only demonstrates pendulum motion, but also helps toshow the laws of conservation of momentum and energy.Delivery Quantity: 1pc,Size: Overall length 9CM, height 11CMColor: silverKind tips1. Package content: only the above package content, excluding other products.2. The size is measured manually, please allow 1-2 cm measurement error3. Due to different displays and lighting effects, the actual color of the item may be slightly different from the color shown on the picture.