Features:Educational science gadget:The pendulum balance ball has excellent educational science gadget. The pendulum balance ball is not only demonstrates a pendulum, but also shows the laws of conservation of momentum and energy.To Kids:Because of the balance swinging magnetic ball various funny way of playing, every kids are very easy to be attracted by newton's cradle, nice gift for them.Metal material:Made of metal, bright and not easy to rust. Each metal ball can guarantee long-term swing. Size 18*11*18.5cm/7*4.3*7.1inch.Easy installation:Just put the frame into the hole of the wooden box to complete the installation. Swing magnetic ball can be used as a creative decompression board game pastime.Gift or toy:For home or office desktop ornament to release pressure and stimulate aspiration. Also good for birthday gift and kids toy.Specifications:Material:MetalColor:SilverSize(about):18*11*18.5cm/7*4.3*7.1inch(L*W*H)Package Included:1pc x Balance Steel BallsNote:1. Due to the light and screen difference, the item's color may be slightly different from the pictures.2. Please allow 0.5-2 cm differences due to manual measurement.