Description:A device that demonstrates a pendulum, and shows the law conservation of energy.A fantastically relaxing object to have ticking and clicking away as you are working, play or rest.Made of metal and ABS plastic material, it is bright, preservative and rust-proof.There are three sizes to choose from: S, M, L.It is suitable for office, home and other indoor places.Item Name: Newton CradleMaterial:ABS,MetalSize Details:[Our Size S] Length: 8.5cm/3.3", Width: 7cm/2.8", Height: 9cm/3.5" (Approx.)[Our Size M] Length: 13.5cm/4.9", Width: 11.5cm/4.5", Height: 13.5cm/5.3" (Approx.)[Our Size L] Length: 18cm/7.1", Width: 15cm/5.9", Height: 18cm/7.1" (Approx.)Notes:Due to the light and screen setting difference, the item's color may be slightly different from the pictures.Please allow slight dimension difference due to different manual measurement.Package Includes:1 X Newton Cradle