Now includes Spring Heel Strap for streamlined comfort and easy on and off * Patented Nature"s Wing Propeller Fin Technology with four (4) material compounds for ultimate performance and light weight * Semi-rigid battens and rubber flex channels within the blade precisely control the shape of the blade during the fin stroke to optimize power and reduce drag * Oversized side rails add rigidity to the oversized blades for increased lift power and efficiency * Ergonomically designed foot pocket accommodates virtually all foot sizes and boot styles