Highest Quality,Burst Resistant Exercise Balls for Sitting, Stretching and Strengthening.At work or in the gym, Exercise Balls help you to improve core stability, strength, balance and awareness. While at your desk, sit on a Ball Chair to engage in Active Sitting. When exercising, incorporate a ball into your stretching and weight programs to improve coordination and stability. Keep kids sitting active on a ball while watching TV or playing video games. An Exercise Ball is even great for relieving discomfort before, during and after labor.Burst resistant up to 285 lbs(130kg).Static load rated to 1,000 lbs(455kg).The Classic Exercise BALL Chair is made from a PVC base. As the name suggests, this ball is suitable for both exercise use or as a chair. Available in 4 sizes to accomodate different heights.