HIGH QUALITY MATERIALThis Newtons Cradle Balance Balls is made of high quality metal material, sturdy and durable to use and and the unique design idea make an impression. GREAT DECORATION GIFTPull one or more of the balls, release them and the same number of balls will swing on the other side. Elegant decor and stylish design make it a great decor for your bedroom or office. PERFECT AS A GIFTThis Newtons Cradle Balance Balls can widely used for home / office desk decoration or birthday gift. And suitable for children to experience the fun of mechanics in the process of playing this fun gadget. HELP RELEASE STRESS Because of its various funny way of playing, every kids are very easy to be attracted by newton's cradle, nice gift for them; and as office desk decoration, it can help you release much pressure when see the swing ball Educatioanl Toy This Newton's cradle balance ball toy is a good practice of physics in action demonstrates the principles of kinetic energy and conservation of momentum. Educational Science Balance Balls Stress Relief Toy When feeling tired of studying and working, you can stir balls to hear the clinking sound to ease. Pull back one or more of the balance balls, release them and the same number of balls will swing up on the opposite side. Material: plastic + metal small ball Size includes: small: 140 * 178mm, medium: 180 * 228mm, large: 225 * 265mm Color: silver brown Package includes: 1pc * Newton pendulum