Yin Yang Therapy Balls

History: First produced during the Ming Dynasty, (1368-1644) iron balls have long been famed as one of the "three treasures", of Baoding China. Produced by skilled Chinese craftsmen, iron balls were originally solid, but are now hollow. Baoding balls are thought to exercise hand muscles, improve brain function and reduce stress when used as alternative medicine to stimulate the acupuncture points on the hand. 1.5" diameter.