This is the Oceanic Viper 2 Open Heel Scuba Diving Snorkeling Fins Features: Ideal for all diving and snorkeling skill levels Flexible Power Thrust Channel directs water off the tip of the blade for improved power and efficiency Power Vents reduce stress while accelerating water over the blade Oversized blade produces increased thrust and propulsion Generous yet streamlined foot pocket fits a wide range of boot styles while significantly reducing drag Extremely lightweight for increased performance and ease of travel Open Heel features easy adjust quick-release buckles The Open Heel Viper 2 Fins are ready to propel all of your aquatic adventures. Ideal for any skill level-but they still pack a punch with the performance and aesthetics of an elite model. The Viper 2 Fin includes a precision blend of hydrodynamics for ultimate comfort, efficiency and performance. The Flexible Power Thrust Channel and enhanced channel rails direct water flow off the tips of the fin and now provide uncompromising power and efficiency at a great value. But we didn&';t stop there. New features also include a polished blade and redesigned performance rails to give the Viper 2 a much-needed update. Also available in Full Foot design.