You've seen these exercise balls at the gym and yoga studio. Now experience the benefits for yourself at home. Trim and tighten abdominal, lower back, and leg muscles. Inflates up to 24 inches. Includes pump and fitness guide. Trim and tighten abdominal, lower back and leg muscles . Inflates up to 24 in. Pump and Fitness Guide Included Everlast® Since 1910 - Choice of Champions® The U.S. Surgeon General has determined that everyone should get 30 minutes of moderate physical activity five days of the week.