Activate more muscle with the Rip:60™ StayBall. Designed for high-performance athletes, the StayBall delivers a more dynamic, muscle-building workout. Added weight increases performance in every move. You'll boost workout intensity for faster, more defined results. Target your upper body, lower body and core to get the body you want. Twice as thick as regular exercise balls, the Stay Ball offers more durability and strength for a dynamic, elite workout.