I love that these kegel balls are firm silicone around what I believe is hard plastic with some type of deuce in it to make it feel kind of like a marble is rolling around, but it doesn’t have the noise of a marble, thankfully. The ridges on the balls give a great feel when inserting them. The only thing I would change about the kegel balls would be the grip. It’s a little too stretchy and thin, and I worry that it will damage or break the loop to remove the Kegel balls. If the grip were 4 times as thick, it would be perfect.