The DuraBall Pro is without a doubt the safest ball in the world today. This ball has been tested by several institutions and at a university for 18 months before we introduced it. Because of the new patented material, Duralon, the DuraBall Pro can handle extreme loads and will always return to its round shape even after using it under extreme pressure. Tests at the University of Newcastle showed an anti-burst rating of 1000 lbs. The maximum static weight limit was tested well in excess of 2200 lbs. Available is 45, 55, 65, 75, or 85 cm. 65 Cm ball is available in blue or gray.