“Stability Ball” Seating
http://www.relaxtheback.com/swopper-product-6370282-6389773
http://www.isokineticsinc.com/category/ex_ball_chairs/product/fb_chair
Informative Image: FitBall chair. White ball, approximately 24" in diameter resting in a tubeular frame with five caster wheels and a small back support. Informative Image: Sit-a-Round chair. Black ball. approximately 24" in diameter resting on a five-caster office chair base. Informative Image: Man sitting on Swooper chair while working on a computer. Swooper chair is slightly mushroom-shaped with a spring stem and a rounded seat.
Swooper
FitBall
Sit-a-Round