The FCS SF4 Stretch Quad Fins design features a moderate foil on a wide base, which help to generate significant speed from the initial turn, and a neutral foil along a thin, flat tip. At low speeds, the ample surface area in the tip of the FCS Quad SF4 Fins provides power, giving you the ability to generate speed with ease. As speed increases, applied force will allow the thin tip to twist with the flow much like a birds wing in flight becoming neutral while reducing lift and drag through turns. These cambered foils were developed using a NACA National Advisory Committee for Aeronautics foil in combination with theories taken from sailboard sails. The result on your Quad is a board that is free yet stable at high speed turns. And all these characteristics are enhanced in Performance Core!