-Deep Apnea Carbon Fiber Biaxial Fin Blades measure 80cm long and 20cm wide and are constructed with carbon fiber cloth in two directions, 0 degrees and 90 degrees. Deep Apnea's carbon fiber fin blades differ from other carbon choices in that they are constructed from an aerospace grade of carbon fiber material. This carbon fiber has a high tensile strength to accommodate tension and compression from use at ocean depths. Deep Apnea's carbon fiber fin blades offer proven performance and are available in soft, medium, or hard stiffness. Our Biaxial blades come with a full 1 year warranty.