Comprises five steel balls of equal mass lined up and in contact with each other. When the first ball is raised and released it transmits the force of motion through the stationary balls upon striking its neighbour causing the final ball to arc. This phenomenon on does not occur if you place a disk of deforming material between the balls.Colour may vary.Dimensions: 280mm x 180mm x 290mm.Frame Material: PlasticProduct is fully assembled.