Home Fins Technology Contact About Click to see more... Le Wo Duo Speed Double Concave Asymmetrical Speed Fin, 100% Carbon Fin sizes (cm): 22 25 27 30 33 Sail size (m2): 6.0 6.5 7.0 7.5 coming soon The Le Wo Duo Speed fins have an asymmetrical foil shape, where the concave transfer diagonally from one side to the other and thus prevents spin out on both tacks. The additional cut out at the base makes it possible to use larger sails. To compensate for a difference in how the foil works close to the surface vs. deeper, the concave surfaces are of slightly different size. This makes the fin work equally on both tacks. The concave near the surface is about 10% larger than the concave near the tip of the fin. Boards normally normally travel slightly sideways with the nose pointing slightly upwind. To eliminate this effect, the fin can be built into the base pre-rotated left or right, depending on the tack of the speed course. This way the fin provides optimal drive and the board's nose points exactly where it is going. Even the 22 cm fin can be used with sails up to 7.0. The Italian record of 39.56 knots by Francesco d'Urso was made with this fin. Superior ride comfort, spin out resistance and speed!