This is the 15 inch plasma ball, the ball is 15 inch in diameter. When touch it, the lightning beams will following your fingers and the lightning beams will dance according to the music when turn to the audio functionn. As a senior manufacturer of the plasma lights, besides the 15 inch plasma ball, we have many other sizes for your choice. Range from 3 inch to 20 inch. The 20 inch plasma ball is  the biggest once in China, maybe in all over the world.