SmarterLife Exercise Ball - Premium Quality Yoga Ball For Balance, Stability, Fitness, Pilates, Birthing, Therapy, Office Ball Chair, Classroom Flexible Seating. Maximum Safety You Can Lean On: Our SmarterLife Exercise Ball uses a thicker wall material, which provides a very high anti-burst rating of 2000 lbs. and retains its shape for years. Our stability ball doesn't pop like a ballon if punctured by sharp objects as is the case with lower-quality balls. Instead, it slowly deflates and protects you from injury during rigorous exercise or while using it as a desk chair in your office.