Item Type: Balance Pendulum BallMaterial: ABS plastic, MetalCombined size: Approx. 9.5 x 9 x 7.5cm/3.7 x 3.5 x 2.9inColor: Black, wine red .wang-edit-text{ font-family:'Arial' !important; } .wang-edit-text table { border-top: 1px solid #000; border-left: 1px solid #000; } .wang-edit-text table td, .wang-edit-text table th { border-bottom: 1px solid #000; border-right: 1px solid #000; padding: 3px 5px; } .wang-edit-text table th { text-align: center; } 1Exquisite Production: Each ball has been accurately measured, weight is uniform and consistent, and uniquely selected base and ball are made of high quality materials. 2Long Swing Time: Classic design, due to the resistance of air and friction, the balance ball can last 1520 seconds and it lats longer time. 3Multiple Ways Of Playing: For example, one ball at one end hits neighbor, the ball at the other end hits air, while ball in the middle stays still. 4Relieve Stress: Balls toy is a charming desk decoration that can not only add beauty to the room, but also relieve your stress when playing. 5Educational Significance: Balls toy is also a perfect school education gadget, which can guide children to understand meaning of energy conservation.