I thought the ball would be larger, and I would be sitting a bit higher... in order to achieve that, I had to over inflate the ball, giving me less movement and not very intense use of back or core. I imagine it will be good for working out, but that's not why I purchase it.
I've had this chair for about a month now and I'm glad I finally bought it after days of leaving it in my cart thinking about it. It's comfortable and I find myself much less sore in my neck and shoulders at the end of an 8 hour day. I also find that I move more and notice right away if I start to slouch. I work from home so I literally sit ALL DAY; after spending $200 on a ergonomic office chair two months before I wish I just bought this in the first place.
This product was everything I expected. Assembly was relatively easy except getting the metal bars into the holes on the base. The angle of the threaded bar ends did not quite match the hole angles in the base--I had to ease each end of a bar in at the same time. Took some maneuvering, but got it done. Several co-workers expressed interest in getting like chairs.
I purchased this to use at my desk. It is much more comfortable than I expected. It feels like I am doing something good for my body. I am certain that I sit up straighter without having to think about it.
I bought this to replace an older ball I had that popped from old age but it didn't have the base support with wheels. This new ball enables me to roll around as needed without losing my good posture!
I love this chair! When I first sat down at my desk I felt like I was on the floor after sitting in such a high office chair for so long. But actually this is the perfect height. My wrists are level and my eyes are even with the monitor (not looking down).
Bought item as recommended by Physical Therapist. Previously used similar item in office setting. Great option to minimize negative effects of chronic desk work.