Equipped with a unique patented - technology at its bottom part, the ball chair guarantees an anti-rolling system thanks to its weighted and non-slip base. (Culbuto effect, always returns to its base) Either you want your seating experience harder or softer, you can adjust hardness and height of your for a perfectly adapted office chair thanks to an easy access to the valve at the bottom. The ergonomic ball chair includes: - an ultra-resistant polyester cover, stain resistant, removable, machine washable and certified by the Oeko-Tex 100 label. - an inflatable ball made of high-density, phthalate-free polyvinyl chloride (PVC), resistant and shatterproof. (such as Swiss Ball, Gym Ball, Klein Ball or gymnastic ball) - a hand air pump and an inflation kit" the ball chair guarantees an anti-rolling system thanks to its weighted and non-slip base. (Culbuto effect, always returns to its base) Either you want your seating experience harder or softer, you can adjust hardness and height for a perfectly adapted office chair thanks to an easy access to the valve at the bottom. Base Finish: Blue Turquoise