The Marquis Benwa balls are perfectly weighted, velvety smooth and cool to the touch, each movement causes the smaller inner ball to shift. Kegel exercises are one of the best ways to tone, tighten, and strengthen the vaginal walls. Just inserting this set of Kegel balls daily and letting the weight of the velvet balls provide gentle resistance can tighten the pelvic floor muscles, tone the vaginal walls, and help you achieve better and more frequent orgasms. With no moving parts or batteries to replace, these compact pleasure toys are a must for any woman!