The new Callaway Big Bertha OS irons have a cage-like structure (similar to a hollow design) that eliminates metal from specific areas inside the body. The strong, light frame is a clever way to move mass and enhance the club's forgiving qualities.
For instance, it allows a 90-gram tungsten weight to be placed low and in the center of the head, which lowers the CG (center of gravity). As a result, the long irons launch higher shots that carry farther than with the current hollow-bodied Big Bertha. As the set progresses to the short irons, additional mass positioned slightly higher helps raise the CG for a more penetrating flight.
The Big Bertha OS also has an upgraded face cup -- this marks the third year that Callaway has featured the technology in irons. A thinner "hinge" along the perimeter of the face cup leads to added face flex and more ball speed than before. Plus, the top line of the face cup is thicker than the bottom, which means the fastest part of the face is more in line with where you typically strike the ball.
These max game-improvement irons come with True Temper Speed Step 80 steel and UST Recoil ES 460 graphite shafts. The clubs are also available in senior and women's versions. They have lighter heads as well as weaker lofts in the long irons. In stores September 30. Set of eight: $1,100 steel; $1,300, graphite.