I've had a couple fit/gym balls that were flimsy. This one is of much thicker material. I would make one strong suggestion however: info on the internet gives a range by your height to determine what size ball to buy. And this one came with a measuring-like tape and instructions to blow it up so the tape ends meet. If I had done that though, the ball would be 15cm too big! And once you let air out, the ball no longer has the same firmness. The best way to get the right height is to stand next to it while inflating. It should come to your knees ...Read more