100% brand new and high qualityThe set of balance balls is particularly suitable for the place such as office， desk table，computer table etc.It is a best and useful gift for children to arouse his/her interest in physics.Not only demonstrates a pendulum， but also shows the Laws of Conservation of Momentum and Energy.Friction and damping effects are also observedMaterial:Solid steel ball，Nylon plumb line，ABS plastic frames and base.Dimension: approx.15.7x8.4x11.6cm/6.18''x3.30''x4.56''(LxWxH)Color: Black+Silver Quantity:1PcNote: Due to the difference between different monitors， the picture may not reflect the actual color of the item. Thank you!Package includes:1 x Newton's Cradle Balance Ball