The Aqua Sphere Microfin Swim Fin is a short blade training fin for a leg muscle work out. This unique structure acts specifically on the areas that competitive swimmers need to strengthen. A closed heel foot pocket is fitted to efficiently transfer power from foot to fin while the short blade is calibrated to allow for a consistent kick tempo while maintaining proper technique. The Aqua Sphere Microfin Swim Fin features top quality materials that provide efficiency, durability and comfort while virtually eliminating leg cramps.