The Luna Ball System includes two 28-gram balls, two 37-gram balls, and a silicone girdle that allows you to change weights of the balls as your pelvic muscles become stronger. Once you've inserted them into your vagina, squeeze your pelvic muscles and the balls inside the girdle will create a pleasing vibrating sensation that will “tickle” your g-spot. If only sit-ups had this little thrill! Use them daily.
A Fairy Godmother personal note about Luna Balls (and Smart Balls): After two babies and now peri-menopause, when I started using pelvic strengtheners I couldn't keep them in while standing up. So I had to start out using them lying down, putting them in for 15 minutes when I went to bed. I read for a little bit while doing the kegel-squeezes. I'll never go dancing with them in but better muscle tone is really important. Use them daily for 15-30 minutes. Once you can keep them in comfortably while you are upright, put them in while you are doing other things, your PC muscles will naturally contract to work to prevent the balls from slipping out and you'll get even stronger.