Milliard Gym Ball Base for Fitness, Yoga & Exercise Balls - Fits Any Size Ball Do you ever have a mess of fitness balls rolling around in your storage space? Milliard Gym Ball Base makes storing fitness balls easy. Simply place the ball on the base and know that its secure until you need it. The fitness ball base fits fitness balls of any size. 20" wide and 2" tall. Designed from durable and sturdy plastic. Easy to assemble and disassemble.