Promate Pro Blade Scuba Diving Open Heel Fins Rubberized side ribs improve elasticity and stability. Easy Adjust Quick-release fin buckles. Channel Thrust Technology system for optimal water channeling Maintaining optimal thrust throughout every phase of the fining stroke minimizes fatigue Upper and lower stabilizers help transfer energy from foot pocket to the blade Soft rubber foot pocket, with ribbed insole for an improved fit and a dramatically more efficient fin stroke