Isokinetics Inc. Balance Exercise Ball Chair Color:Purple This ball chair comes with 60mm office size wheels & 52cm exercise ball Standard Height Plastic Frame Ball Chair with reinforced black metal ball retaining bar. The chair comes with Exercise Ball Measuring Tape & Starter Pump The exercise balance ball chair is super comfortable and helps prevents slouching These chairs don't cause stiffness from prolonged sitting like traditional chairs Isokinetics exercise chair is of the highest quality, well-constructed and durable It is very effectiveness in supporting core muscles and reducing back pain Great for anyone spending long hours online for work or play