Highlighted by a fully redesigned longer foot pocket, these fins offer a great combination of thrust force and comfort. Design features unlock the ability for maximum efficiency with minimal effort. Features soft longitudinal inserts that allow for a controlled deformation of the fin blade while kicking. Strategic channel shape moves a greater amount of water resulting in more thrust for the same effort. Optimize Pivoting Blade (OPB) allows the blade to maintain an optimal angle throughout the kicking cycle, which minimizes fatigue and produces fluid movement through the water. Tri-Material construction provides maximum elasticity, high durability and resistance to aging. Two year limited warranty.SizeSmallRegularExtra LargeBlade*15 5/16" (39cm.)15 11/16" (40cm.)15 11/16"(40cm.)*Blade is measured from the end of the footpocket to the end of the blade.