The product is shipped based on the COR or TAMANHO of the main image of the product page.Arc-shaped Newton's Cradle Balance Ball Newton Pendulum Perpetual Motion Instrument Science ToySpecificationName: Newton pendulumTAMANHO: 26* 16 *23cm sphere diameter 1.6cmMaterial: plastic + nylon line + steel ballFeatures1.The principle of conservation of momentum in physics toggle one, two, three ball, can see different effects, fun unlimited2.Not only demonstrates a pendulum, but also shows the Laws of Conservation of Momentum and Energy.3.Friction and damping effects are also observed.4.Often used as a toy to amuse people.5.Includes steel balls, plastic frames and base.6.Great gift for everyone. Package included1x Newton's pendulum