These steel balls originated in the Chinese city of Baoding during the Ming Dynasty (1368-1644 AD). According to traditional Chinese beliefs, the vital organs of the human body are all connected to the fingers. By manipulating these iron balls, it stimulates the circulation of blood and energy throughout the body. Take the challenge of spinning these iron orbs without dropping them. Hollowed balls are outfitted with sounding plates to produce a jingle as they are rotated. Set of two in an embroidered case. The extra small or kids size is less than 35mm in diameter. There are more than ten designs : Panda, Elephant, Dolphin(Yin Yang), Rainbow, Sun & Moon, Dragon & Phoenix, Frog and Silver (Chrome). The designs will be randomly assigned. Please put your design selection in Comments if you need a special design.