Ben Wa balls

They may also be used for a medical purpose, such as to increase the strength of the pelvic floor muscles, much as Taoist sexual practices have been used for centuries[5] and the Kegel exercises are used today.

Similar to Kegel exercises, Ben Wa balls and other shaped vaginal weightlifting equipment are recommended by gynecologists and obstetricians to increase vaginal elasticity and bladder control.

[6] It is possible to leave the balls in place in the vagina all day, or use them while seated in a rocking chair.

[7] Health experts caution against prolonged placement of foreign objects in the vagina due to the risk of infection.

Originally they were made of a single ball placed in the vagina, used to enhance the act of sexual intercourse, but then evolved into multiple metal covered balls linked by either a chain or silk string for easy removal.