Svakom Nova Ben Wa Balls are made of silicone which is 100% waterproof. According to the kegel exercise theory, these exercise courses were designed especially to help those who have a loose vagina after giving birth. Three sets of Nova balls have three gradual increased weights for different exercise needs. Effective kegel exercise helps to strengthen woman's PC muscle, improving health while bringing sexual benefits and satisfaction. For daily exercise or postpartum recovery, Svakom Nova balls are the perfect choice for you.