Description: Pendulum Ball: So some simple assembly work is needed before using it. After you have it you will play it with a great sense of accomplishment. How to Use: To make the balls move just push it slowly with the supplied strip then gently loosen it. Desk Office Decoration: Show some character and express your science and physics with this decorating of your office space. Educational Toy: Use this in class and share with your friends and family the exciting physics and science. Quality Materials: Made of durable metal material also good for birthday gifts and toy. Specification: Material: Wood Base Metal Stand Solid Steel Ball Size: 23cmx14cmx17cm/9.06inchx5.51inchx6.69inch Package Includes: 1 Metal Cradle Balance Ball Note: Please allow slightly errors due to manual measurement and different monitors.