The CanDo Core-Training Vestibular Dome balance exerciser can be used as either a vestibular board or as a vestibular ball. In either case, the ball can be inflated or deflated to adjust the difficulty level. Comes with resistance cords with handles for a dynamic workout. Dome measures 21” in diameter, the perfect size for either 1 or 2 feet. Dome is one continuous unit. Comes with 6” pump.