The Kore Kids Adjustable Standard Wobble Chair is great for helping your pre-teen work and learn effectively. The innovative Kore Wobble Chair with its gently-rounded bottom encourages active sitting and allows one’s knees, hips, and back to find comfortable and ever-changing positions; continuous movement increases Secondary Focus. Anti-Tip Safety-A patented Anti-Tip safety ring on the base prevents tip-overs and falls. Manufactured with Antimicrobial Protection against the spread of common bacteria; FDA approved and successfully tested to reduce up to 99.9% of common bacteria including E. coli, listeria, and S. aureus.Great for younger children, the seating height can be easily adjusted with the 360° Actuator Ring to grow with your child. Suggested for ages 9-14; Grade 4-9; child height 53”-70”.