The company says the Caliber is the most radical departure from traditional solid rubber core construction in nearly 30 years. A patented hollow metal core creates significant rifle spin, while reducing side spin, allowing the ball to travel along a straighter trajectory similar to a bullet leaving the barrel of a gun. Putting is improved due to the perimeter weighted design of the ball. This Caliber is ideal for the golfer who puts an emphasis on accuracy, and is designed for swing speeds under 100 miles an hour. This is a softer version of the original MA-1.0 hollow metal core golf ball.