The majority of swim fins make it impossible to perform a proper breaststroke kick but not the FINIS Positive Drive Fins. With their elliptical blade, they make it possible to maintain correct technique during every stroke. Breaststrokers and IMers: Rejoice! Features Elliptical blade for easy propulsion during all kick styles. Asymmetical blade design allows for natural inward supination kick. Adjustable heel strap allows feet to flex naturally. Increases leg, ankle, and foot strength. Flexible rubber construction. For more information on swim fins, read How to Choose Swim Fins. Details Fabric: Rubber Closure: Slip on Adjustable: Heel strap Country of Origin: Imported