TaylorMade Golf's rac CGB irons, (Center of Gravity Back) feature a low and deep centre of gravity that helps make possible a remarkable combination of distance, control and forgiveness. Five key elements contribute to the CGB's high level of performance. (1) Pull-Face construction, featuring a clubface fashioned of high-strength C455-stainless steel, milled on both sides and created separately from the clubhead. Making the clubface separately allows for the face to be exceptionally thin yet strong. TaylorMade engineers took the 13 grams saved by this thin clubface and positioned it back and low in the clubhead. (2) The rac CGB incorporates a hollow top-line across the top of the clubhead from the hosel to the toe, creating a deep hollow cavity to reduce weight in the clubhead. (3) the rac CGB's Performance Cartridge, comprised of tungsten-loaded, high-density urethane and five metal inset rods precisely positioned to centralize weight in the clubhead. This concentrates mass behind the hitting area to promote power and simultaneously contributes to the deep-back CG position, which is what makes the rac CGB so easy to launch. (4) TaylorMade's renowned rac Technology, distinguished by two Feel Pockets, milled directly into the cavity. These help to channel impact energy to strategic areas of the clubhead, promoting outstanding feel. Because the rac CGB's face is extraordinarily thin, the Feel Pockets of the rac CGB vibrate more freely, further enhancing feel. (5) TaylorMade's Ascending Mass graphite and steel shafts, in which the mass of each shaft increases as the length decreases. The Ascending Mass results in lighter-weight long-irons, promoting greater distance and control; while the slightly heavier mass in the short-irons delivers added feel that can help players to better execute scoring shots. rac CGB irons also feature an exceedingly large, deep back cavity and tall clubface, both of which contribute to an extremely high MOI, for excellent forgiveness. Although a taller clubface typically precipitates a high CG, TaylorMade engineers were still able to position the CG low and deep by virtue of the CGB's advanced design and technologies.