http://www.sportyhabits.com/cosco-fitness-gym-ball - This Gym ball is also known by a number of different names, including exercise ball, Swiss ball, Pilate's ball, sports ball, fit or fitness ball, stability ball, therapy ball, yoga ball, balance ball, body ball, or birth ball. Swiss balls are large, heavy-duty inflatable balls with a diameter of 45 to 75 cm (18 to 30 inches).
