Features: Made of high quality plastic and iron material, sturdy and durable to use. Elegant decor and stylish design make it a great decor for your bedroom or office. Designed according to the Laws of Conservation of Momentum and Energy, the balls will swing one to one by first pushing one ball, no electricity needed. Great toy for both adults and children to relieve their stress, can also be used as a hypnosis tool. Widely used for home / office desk decoration, art craft gifts or wonderful birthday gift. Specification: Material: Plastic + Iron Color: Orange / Purple(Optional) Battery: 4 pcs AA batteries (Not included) Size: Approx. 16*12cm / 6.29*4.72inch Package list: 1 * Desktop ornament