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 medium size is 50mm in diameter. There are more than ten designs : Panda, Elephant, Dolphin(Yin Yang), Rainbow, Sun & Moon, Dragon & Phoenix, Frog and Silver (Chrome). Please put your design selection in Comments or send us an e-mail on your design selection after you make the order.