The Wilson Staff D300 SL irons are designed for the Distance player needing power, accuracy and a confidence-inspiring look at address " feature Speed Sole Technology which allows for a thinner face-to-sole transition resulting in driver-like CT ™s, faster ball speeds and longer distance. Speed Sole Technology - Creates a thin face-to-sole transition that expands the sweet spot and increases CT and ball speeds for driver-like distance. Heel & Toe Weight Pods - Position the weight low and around the perimeter of the club head for increased forgiveness. Right Light Technology - Helps players to swing the club faster with the same effort and faster swing speeds deliver more distance.