The Original Evolution Stability Ball Chair leads the pack as an ergonomic, reliable, and safe active seating option. Ideal for all home and office use where improved posture, core strength and overall back health is the goal. Improved posture and core strength can reduce back pain and sitting fatigue. Evolution Ball Chair Kit includes a high quality height adjustable base (risers included additional height), anti-burst stability ball, standard and rolling casters, and hand pump. • Height – Base 8.5 inches (w/o inserts) to 10.5 inches (with inserts) • Width – 19 inches • Depth – 19 inches • Weight – 9 lbs • Stability Ball – inflates from 50cm – 60cm (adjust by inflation level) • Weight Capacity – 300 lbs