Put us in a chair and we often slouch or resort to other less-than-ideal positions. To help counteract those habits, we created our adjustable Balance Ball® Stool. Fitting most standard desks, the instability of the dome-shaped seat causes micro-movements to aid core strength, posture and circulation. Instability-induced micro-motion firms core and improves circulation and posture Stool height ranges from 18″ to 23″ to fit most standard desks Stable, 360° swivel base allows for easy movement Lightweight and compact with easy-glide caster wheels that lock Anti-burst, domed Balance Ball seat Includes easy-inflation pump Measurements: Adjusts from 18″ to 23″ height, seat diameter of 45cm; 14.33lbs. Weight Capacity: 300lbs. Materials: PVC, PP, & Nylon. Resources: Care, Setup, & Tips.