The vibration (non-electronic) produced by the impact of the inner ball of the Chinese balls against the walls of the vagina causes an involuntary and continuous contraction of the muscles that surround it, increasing blood circulation, lubrication and muscle tone. Chinese balls are a passive gymnastic device that is inserted into the vagina to increase the muscle tone of the pelvic floor and prevent its deterioration, and can also be used as a sex toy. Chinese balls are a passive gymnastic device that is inserted into the vagina to increase the muscle tone of the pelvic floor and prevent its deterioration, and can also be used as a sex toy