For a more efficient finning action.The use of stiff material in the sole reduces the flexibility of the foot, achieving more efficient finning action.The neoprene area around the ankle is made of super-elastic material. The lower section, in standard neoprene, ensures warmth and adherence.YKK zipper, with internal neoprene gasket to limit water seepage.Reinforcement on the toe and heel.Rear notch for securing the fin strap in place.Raised heel to keep you more balanced while carrying all the weight of your diving equipment.