The Wilson Staff Di 9 Distance Irons feature a cavity back design with a "Shock Trap" urethane insert for any player looking for more forgiveness and distance in their irons. The "Shock Trap" urethane insert is located in the heel of these irons to deliver a perfect combo of power and forgiveness. These high MOI irons have an increased hosel length and a sweet spot located more towards the toe to create a bit of a draw bias.