--High Quality， stylish and innovative design. Solid wood foundation & stainless steel swinging balls.--Great Gift Idea - available in small， medium and large size. Something gets everyone's affection. Own your very own piece of scientific history.--University - an exquisite decoration that can be placed in kitchen， living room or office.--Multi-function - excellent educational & science gadget: own your very own piece of scientific history and explore significant values of physics. Gorgeous and Elegant ornamentation.Psychological purpose， help with insomniaFeatures: --Principle: Not only demonstrates a pendulum， but also shows the Laws of Conservation of Momentum and Energy. --Material: Balance Balls Desk Toy * 1， Stainless steel frame and balls， Nylon thread，Wooden base--Attention: Friction and damping effects are inevitableProduct Dimensions: 5 x 7.5x 5.9inches