This is the Mares Volo Power High Quality Open Heel Scuba Fins with OPB Features: Completely new & redesigned version of the Volo Fin! New Volo Power Fin - Longer than the original Volo fin New Volo Power Fin - 25% more efficient than the original Volo fin Quick release, quick-adjust buckle makes adjusting a snap OPB (Optimized Pivoting Blade) Fin Technology that ensures the blade is always at an optimal angle during both the up and down stroke Channel Thrust Technology system for optimal water channeling Maintaining optimal thrust throughout every phase of the fining stroke minimizes fatigue Soft anatomical foot pocket, with ribbed insole for an improved fit and a dramatically more efficient fin stroke High performance with minimal exertion, comfort and light weight. The anatomic foot pocket features interior ribs that improve fit, eliminate foot suction and prevent foot pocket flexing which transmitting more power to the blade. Ideal for women, kids and all divers who want the easiest kicking fin in the market.