SPEEDSHELL Face Insert with H.O.T. Face Tech: A re-engineered face insert is our largest to date, wrapping further around the toe and sole area. A larger insert paired with H.O.T. Face technology delivers 23% more face flex than the previous generation DARKSPEED irons, unlocking faster speed, higher launch and even more distance. New Internal Adaptive Weighting System: A re-engineered PWR-BRIDGE weight positions the CG lower for improved energy transfer and higher launch resulting in more playable distance. Hollow Body Construction: Taking inspiration from a metalwood design, a hollow body construction in every iron improves weight distribution and creates a more unsupported face to unlock maximum distance potential. Tuned Acoustics & Feel: The hollow cavity is filled with a soft foam that damps vibrations for exceptional sound and feel.