New Oceanic Viper Open Heel Scuba Diving Fins - Black (Size 9-11/Regular) 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