The revolutionary design of the Oceanic Manta Ray fin was inspired directly from the shape and bio-mechanics of marine animals. By combining three different materials to simulate bone, tendon and fin, we&';ve created a blade design that provides maximum power, speed & efficiency while also remaining extremely lightweight & durable. Of course, it&';s not all nature&';s technology, we added some of our own as well. Our new soft-pad heel spring strap has a unique ergonomic finger-loop that makes getting these fins on or off in any situation a snap. We&';ve also replaced the standard buckle attachment points with our new Easy Buckle Adjustment (EBA) system. The EBA system allows precise adjustments for a custom and comfortable fit at anytime and without tools. This unique and unparalleled combination of materials and technology will deliver performance where ever and whenever you need it; from demanding currents and rough surf to long surface swims, the Manta Ray will get you there. Techno-Polymer Blade - Advanced materials provides the strength of bone to maximize power, speed & efficiency, while being extremely lightweight & durable. Power-X System - This revolutionary material acts as tendon & joint, optimizing propulsion by flexing during the downstroke and releasing stored energy prior to the upstroke. Power Channel - The flexible center channel simulates the elasticity of skin by directing water flow off the back of the blade for increased thrust. Soft-Pad Heel Strap - Our newly designed heel strap has a comfortable and ergonomic finger-loop which allows the fin to be easily removed & replaced, even with thick neoprene gloves. Easy Buckle Adjustment (EBA) - Our unique EBA buckle adjustment system allows for more than 2 (5 cm) of precise adjustments for a custom fit without tools. Winglets - These have been positioned along the length of the blade to increase efficiency and improve maneuverability.