BOSU® Ballast Ball. Welcome to the new school stability ball training. It stays put and won't wander around the gym. You can easily stack multiple Ballast(tm) Balls on top of each other, so gone are the days of unsightly storage contraptions. As if that wasn't good enough, the Ballast(tm) Ball opens the door to exercise progressions and dynamic drills that you simply can't perform on a regular ball. The ball just got better! The BOSU® Ballast(tm) Ball includes foot pump and workout DVD