Fitness Fins are short, dual intensity fins with stiff blades which create maximum resistance in the water. Strengthen leg muscles - added resistance increases the workload on your leg muscles which increases strength and endurance. Increase workout speed - Fitness Fins add extra propulsion to the stroke, which increases speed with minimum effort leaving you free to ingrain correct technique. Develop ankle mobility - The increased surface created by the Fitness Fins forces ankle extension during kicking, which makes the kick more propulsive and efficient. Features & Benefits Speedo Biofuse technology – for maximum comfort and fit 100% Silicone for excellent comfort Strengthen leg muscles - added resistance increases the workload on your leg muscles which increases strength and endurance. Increase workout speed - Fitness Fins add extra propulsion to the stroke, which increases speed with minimum effort leaving you free to ingrain correct technique.