The new and updated Liberator fins features a blade with flexible material near the side ribs, enabling it to flex from the base and generate propulsion with a gentle kick. Winglets at the blade tip prevent turbulence, resulting in a water flow effect that is converted into propulsion. Features: Perfect for beginners. More power with less exertion. Modern update of the original Liberator that was around for 30 years. Updated 3D strap for improved comfort and durability. Anatomic Fin Strap The AFS is anatomically shaped to offer a balance of flexibility and control to increase comfort, power transfer and to significantly reduce heel slippage found in many standard flat fin straps Angled Blade Design (A.B.D) The Angled Blade Design accommodates for this anatomical characteristic and ensures maximum efficiency throughout the kicking cycle. EZ Strap Buckle System Quickly and easily adjusted with minimal effort. Adjustment can be made while the fins are worn.