Feature:1. Stress Relief: This balance ball is a charming desk decoration. Not only will it add beauty to the room, but it will also relieve stress while you play. It's a cool and fun game for office workers to avoid anxiety.2. Swinging Process: Five balls are hanging side by side and touching each other and the center of the ball is in the same line, first the left ball is pulled away and then let go of it, the right ball to it collides and stops, while the right ball swings up and swings roughly the same distance as the left ball.3. Momentum Transfer: If the two balls on the left are pulled away at the same time, then, after the collision, the two balls also stop, and the two balls on the right swing up, and when the right ball swings back and the left ball collides, the momentum will be transferred to the left ball.4. Edutainment Using: The balance ball is also a perfect schooling gadget. It can guide children to understand the meaning of conservation of energy. Let children receive the baptism of science while playing.5. Ideal Gift: The classic design makes it a great gift for your child's family, friends and colleagues, or to put on your desk and coffee table at home for a decorative effect, while stimulating the children's interest.Specification:Item Type: Desktop Balance BallsMaterial: MetalSize: Approx. 18.5 x 18 x 11.5cm / 7.3 x 7.1 x 4.5inPackage List:1 x Desktop Balance BallsNote:1. Manual measurement may have 0‑1cm error. Please make sure you don't mind before ordering. 2. Due to differences in different monitors, the picture may not reflect the actual color of the item. Thank you!