In January of 1998, Callaway Golf introduced a new stainless steel iron. It featured a Multi-Layer Design, a 360-Degree Undercut Channel, and a patented S2H2 and Tru-Bore design. This iron set the standards and foundations for what was to become a legacy of high-performance golf irons. One year later, the Big Bertha X-12 and X-12 Less Offset Irons became the most popular golf irons in history.

Today, Callaway irons tradition of the X-Series iron performance lives on in the X-18 Irons and X-Tour Irons. The X-18 and X-18 Pro Series Irons feature a deep 360-Degree Undercut Channel that optimizes the center of gravity. This helps players keep the ball on target from any distance or turf condition. The Notch Weighting adds stability to the swing. The True Bore technology improves control by enabling the shaft to extend through the hosel to the sole.

Callaway engaged the professional services of Roger Cleveland to create the Callaway irons X-Tour series. These irons are designed for the advanced or professional golfer. The Callaway X-Tour Irons are comprised of a notch-weighted, cavity-back head to which the face plate is laser-welded. The back cavity is precision-milled, which makes it a perfect fit for the face.

Both pieces of the X-Tour iron club head are composed of soft, 1020 carbon steel. This two-piece forging allows the company to incorporate the technologies that had gained popularity in other Callaway products. The Callaway X-Tour Irons have been in use on professional golf tours, and Callaway irons are considered some of the leading golf clubs in the world. Phil Mickelson and Annika Sorenstam are among the pros that are now using the X-Tours.