Mares Volo Power Scuba Dive Fins Mares has improved the Volo, an already exceptional fin, to provide unbeatable performance. It"s the world"s only fin with eight patents, and has become the benchmark for the most demanding divers. Thanks to the combination of the O.P.B. and Channel Thrust systems that we have refined even further, the Volo Power offers more power, more thrust, and requires even less effort. MARES VOLO POWER TECHNICAL SPECIFICATIONS: Type: open heel Operating principle: O.P.B. system (patented) Channel Thrust Technology (patented) Materials: thermoplastic rubber technopolymers Blade (regular)length: 39 cm / 15.5 in Thrust area: 760 cm2 / 117 in2 Buckles: ABS system (patented) Mares Volo Power Sizes: Small, Regular, Extra Large Mares Volo Power Color: Black/Silver