This Newton cradle is made of high quality ABS plastic, a sturdy fishing line and a sturdy metal ball. It is bright, preserving and not easy to rust. It can be served for a long time. Shows not only a pendulum, but also the laws of obtaining momentum and energy. Perfect educational toy to catch the story and mystery of science. It is a very fun decompression toy that allows a ball to hit and swing other balls. Joyful to decorate the office, home and other interiors. This swinging cradle can explain to your child that physical knowledge and Newton's story also help to explore the mysteries of science, a fun gift for Your friends, your family and your children. How to play: Pull back one or more balancing balls and let them go. The same number of balls swing up on the opposite side. Size: 14cm x 11.5cm x 14.5cm.