This is a great pair of Hydro Blade Fins. These super fins feature: Three-material bounding structure EVA fins blade TPR foot pocket TPR extending from the foot pocket through the length of the blade to improve lateral flexibility Black polyurethane rib stiffeners governing longitudinal flex whilst maximizing thrust Patented quick-release fin buckles Maximum thrust and lateral stability Revolutionary ridges on the blade provide stability One hand release style quick-release, and quick adjusting buckles Medium to stiff blade for medium to stronger swimmers Revolutionary ridges also aid in channeling the water for a more efficient kick Powerful fin Using computer aided technology, thermoplastic is incorporated into the blade for optimal blade curvature Efficient forward propulsion Revolutionary ridges on the blade provide stability during the kicking stroke and aid in channeling the water efficiently along the entire length of the blade. This results in a more forward thrust and greater power. Using computer aided technology; we incorporated a thermoplastic center section into the blade. This allows precise blade curving during the kicks, which results in more efficient forward propulsion of the diver. The fin is designed with a comfortable foot pocket and easy to adjust one hand release style fin strap buckles.