SVAKOM Nova Ben Wa Balls are made of silicone which is 100% waterproof. According to the kegel exercise theory, we designed these exercise courses 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. Dimension:Single Ball : Dimension:36X135 mm Double Ball Dimension(big):32X170 mm.Double Ball Dimension(small):28X162 mm Weight: 49g 75g 95g Water Repellency: 100% Waterproof