Distance-improving F9S irons have a large design in which the mass has been moved to the sides and back to give a low centre of gravity that increases the ball speed and launch angle for optimal distance. Speedback technology with tungsten weights in the heel and toe give added stability and make the club forgiving. The sole design channels more energy to the ball when struck and creates a higher ball flight and more ball speed. The shorter hosel in the 5 and 6 iron lowers the centre of gravity for a higher launch angle and greater distance, while the longer hosel in the shorter irons raises the centre of gravity for a lower, more controllable trajectory.
Milled face and grooves., a CNC milled face has been introduced in a game-improving iron to produce a completely flat surface, precise grooves and exact lofts which gives maximum spin and trajectory control.
Progressive Spin Tech, precision-milled V grooves on 5i to 7i reduce the amount of spin for longer hang time and distance. U grooves on 8i to PW optimise the amount of spin for better control and aim.