Vintage Shou Xing IRON BALLS, which are also known as Baoding balls/meditation balls/Chinese exercise balls/ Chinese Health Balls/Chinese medicine balls, etc. Rotate 2 or more of these balls in one hand repeatedly to improve finger dexterity, relax the hand, or aid in the recovery of muscle strength after surgery.  Cool collectors item. The balls measure 6 1/4" around and look to be made out of marble or something similar to it. In original box with directions attached. Smoke free home.