There are various benefits to using these gorgeous silicone kegel balls. These smooth oval shaped balls are held within a white silicone cage with a love heart end.Each ball features a small inner weight that moves around within the ball. Simply insert the balls,using the silicone cage to keep them in place,also to safely retrieve them and as you move ,the inner weights will click and knock,causing your muscles to spasm. These spasm will arouse your senses and work to effectively tighten your vagina strength. This set of kegel balls included a single ball and double allowing you to build up your exercise. For more comfortable use, it is recommended to use with water-based lubricants . Material : 100% silicone Size: one ball 3.5 x 5.5 Weight of two balls 80 grams, one ball 41 grams.