I bought this ball since I read, recently, a study that people who sit on their butts 6+ hours/ day have a shortened life span. I thought, I sit on my butt for at least 8 at work! Not to mention when I get home and finish up my home-work. So I purchased this ball. I'm up to sitting on it about 6 hours of my workday. I bounce around, move around and it also has made me concentrate more - I get lots done when I'm sitting on it! I think my capacity to concentrate on my environment is lessened when I'm focusing on not falling off of the ball! HAHA! Anyway, this ball is a little less thick than others that I've seen so it's probably not the best one on the market. But it works. Oh, also, the pump they send with it is useless. I used my kid's bicycle tire pump and that seems to work perfectly when it needs some added air.