Description: Excellent educational science gadget. Not only demonstrates a pendulum, but also shows the laws of conservation of momentum and energy. Science toy. When feeling tired of studying and working, you can stir balls to hear the clinking sound to ease. Excellent educational & science gadget, own your very own piece of scientific history and explore significant values of physics. Pull back one or more of the balance balls, release them and the same number of balls will swing up on the opposite side. Great for home ornament, study or office desk table decor accessories, etc. Also good for birthday gift and kids toy. Specification: Condition:100% Brand New Material: Wooden base +5 solid balls + fine fishing line+Metal Bracket Color: As Pictures Shown Size: approx.14cmx14cmx12cm/5.51inx5.51inx4.72in Weight: Approx.519g/18.3oz Occasions: Daily use, Education supplies, Psychotherapy, Birthday present, Business gift Package Included: 1 x Balance Balls Toy Note: 1.When you use this newton's cradle, please move it in a horizontal line, so the lines will not be tangled. 2.Please don't worry, if it was tangled, you could untangle it still, just need some patience.DIY your own cradle! 3.Please allow 1-2 cm error due to manual measurement and make sure you do not mind before ordering. 4.Please understand that colors may exist chromatic aberration as the different placement of pictures.