The Yoga Direct Anti-burst Slow Leak Fitness Ball, made from extra durable vinyl, is tear-resistant so it will endure the most vigorous fitness classes. This 65cm textured fitness ball is perfect for yoga, Pilates and mat exercise to strengthen lower back muscles, abs and glutes. Our slow leak yoga ball is thicker than most gym balls and can withstand 600 pounds of pressure. If this ball ever gets punctured, rest assured, it won't burst. The ...