Smart Balls as mentioned in the book 50 Shades of Grey. These balls are made with medical grade silicon and easy to remove.

They are designed to help you tone your PC muscle and do your kegels. http://bliss-radio.com/to-kegel-or-not-to-kegel-how-to-kegel-correctly/

These silicone Smart Balls are a sexier version of the legendary Ben Wa balls, which have seen a resurgence in popularity thanks to their starring role in an erotic party scene in the best selling novel Fifty Shades of Grey. Whether you want the subtle eroticism the balls provide when inserted, or you’re looking for a way to strengthen your PC muscles (and your orgasms), these balls will get the job done. This is toy is designed to help you achieve more powerful orgasms and G-spot pleasures. Just insert the balls, squeeze them with your vaginal muscles, and tug gently on the cord for resistance exercise. Water-resistant.

Price: $30.00