These beautifully crafted Ben Wa balls can be used to increase the strength of the pelvic floor muscles. They also create a subtle stimulation, not meant to bring the user to an immediate orgasm, but rather to tease! Place the balls under a stream of lukewarm or cold water and the premium borosilicate material will heat up or cool down for enhanced temperature play. Unique design. Use cold/warm water to cool it down/heat it up. Hand crafted and made of borosilicate glass. Shatterproof. Body safe.