Check the listing for details. Mares X-Stream Open Heel Fins. Condition: New with box. Listed at 239.95 USD. X-stream comfort, X-ceptional effiiencyThe X-stream performance, comfort and lightweight design are the incredible result of sixty passionate years at the service of diving. The X-stream is truly a leap into the future, and changes forever how we envision the creation of a fin. More than 2 years of resources, experiments and testing and four Mares patents all concentrated in one unique product.FeaturesBungee StrapRiddled foot pocket avoids "parachute effect"Next generation OPBTri-material blade construction reduces turbulenceChannel thrust technologyDESCRIPTIONThe X-Stream diving fins have a blade length that varies from 34.5 to 38 cm depending on the size. The fins have an open foot pocket. They are made of innovative, high-performance materials and provide superior thrust while minimising leg fatigue. The materials used are 3 specific ones for maximum elasticity, high durability and resistance to wear. The special channel thrust system creates a channel geometry capable of moving more water and creating more thrust with the same amount of effort. The result is an ultra-high performance fin designed for the most demanding divers. The newly designed foot pocket has large perforations (which prevent the so-called "parachute effect") and the joints at the junction with the blade absorb kinetic energy. The blade, with its extremely wide central flap, ensures a strong channelling effect in accordance with the Superchannel principle. Riddled Foot PocketThe perforations prevent stagnating water flow from slowing you down. Eliminating this “parachute effect” you’ll slide faster through the water. Furthermore the openings eliminate any suction effect, making doffing easier.OPB - Optimized Pivoting BladeAllows the blade to maintain an optimal angle throughout the kicking cycle, whereas traditional fins achieve this only during a small portion of the cycle. OPB produces a constant thrust, which minimizes fatigue and produces fluid movement through the water.Channel ThrustSoft longitudinal inserts allow a controlled deformation of the fin blade while kicking. This channel shape moves a greater amount of water resulting in more thrust for the same effort.Tri-Material Construction3 specific materials for maximum elasticity, high durability and resistance to aging. The result is superior performance in all diving conditions.