The FitBALL Exercise Ball from Ball Dynamics is the ultimate for improving flexibility, strength, posture, and cardiovascular fitness. These balls are made of a burst-resistant material that prevents rapid deflation when punctured. Trusted by physical therapists and personal trainers, the FitBALL can withstand weights up to 2,250 lbs. and is available in a variety of colors and sizes. The 55 cm ball is available in your choice of black, pearl, purple, or red and is packaged with a FitBALL poster.