Amazon.com: 55cm, Yellow Smart Self-Guided Stability Ball – Exercise Ball for Exercise, Yoga, Pilates, Office Ball Chair and More, 13 Exercises Printed on Ball for Easy Reference, Prism Fitness : Sports &
Amazon.com: Gaiam Kids Balance Ball - Exercise Stability Yoga Ball, Kids Alternative Flexible Seating for Active Children in Home or Classroom (Satisfaction Guarantee), Blue, 45cm (2.09 Pounds) : Sports & Outdoors