Powercore Wobble Chair

If you are in any doubt about a Wobble chair you have to try one. You WON'T go back to a normal office chair.
 
Choose to sit at whatever height works for you and you'll find your back moving and flexing from the first hour you are sitting on it (660mm - 850mm). I'm confidently predicting that these will replace office chairs in the next few years.
 
Keep in mind that these stools are ideally suited to an electric height adjustable desk. They will be too high (at their lowest point) for normal desktops.