Baoding balls

[1] Intended to improve finger dexterity, relax the hand, or aid in the recovery of muscle strength and motor skills after surgery, Baoding balls work similarly to Western stress balls.

Baoding balls can also be made of solid jade, agate, marble, and other types of stone.

Heavier balls of iron, steel or tungsten carbide require more effort for rotation.

Once this technique has been mastered, the rotation speed can be gradually increased until the balls separate in the hand.

[7] Though unsupported by scientific evidence, 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.