Features: 1.Material: This true balance toy is made of high-quality materials, use nylon line of good material instead of cheap fishing line. 2.Applicability: This perpetual motion desk toy is very interesting. Newton Cradle never gets old.The concept of Newton's cradle is very pleasant.They are great for psychology, science and physics classrooms and are also great for kids. 3.Colorful: This cool things for your room can emit colorful light, the effect is more obvious in the dark, and it is more interesting than ordinary desk toys. 4.Gift: This desk toys for office for adults is an excellent gift. You can give this gift to your children or relatives on Christmas, Halloween, and Thanksgiving.Notice: Actual color may be slightly different from the image due to different monitor and light effect Please allow 1-3cm deviation due to manual measurement Description: Material: glass ball + nylon thread + electronics Size: 12*9*12cm(L*W*H) Weight: 180g Battery:4xAA batteries(not in