Volo Race Fins. A combination of the exclusive and patented OPB and Channel Thrust systems, for a full-foot fin that has no rival. High performance with minimal exertion, maximum comfort and exceptional light weight. It all adds up to no cramps and more fun diving. Orthopedic foot pocket in soft thermoplastic rubber for maximum efficiency and comfort. OPB system with expandable inserts optimizes the thrust angle. Channel Thrust Technology for perfect water flow and exceptional stability.