The SF0102 Imprex Duo fin features TUSA's patented Angled Blade Design and multi-compound foot pocket, increasing power transfer to the fin blade. The Imprex Duo also features a two material design for high performance and reinforced side-rails creating stability, for powerful propulsion without fatigue. The fins Angled Blade Design (A.B.D.) unlike a standard flat fin that inhibits propulsion solely by fault of design. An angle between the heel of the foot and the calf of the leg remains when the leg is extended to kick. This angle causes approximately 10% of the propulsion to be lost. TUSA's Angled Blade Design accommodates for this anatomical characteristic and ensures maximum efficiency throughout the kicking cycle. Fins are equipped with TUSA's EZ Strap and Buckle System. TUSA's EZ strap and buckle system allows fins to be quickly and easily adjusted with minimal effort. Adjustment can be made while the fins are worn, allowing for a precise fit and ease of removal when necessary. The dual material composite fin non-vented blade design provides high performance along with the multi-compound open heel foot pocket increases power transfer to the fin blade. Balanced flexibility gives powerful propulsion without fatigue!