This sail is the cut of an S26 but the material of an S25 Naish Fore 4 sail. The material used is Naish's X1-66, a material that was developed within the company over a number of years and noted for its durability and lightness. We believe this material was mistakenly used by the factory who produced the sail instead of the XS-1577 film (the sail cloth used on S26 and current Naish Force 4 sails). This sail will still performed superbly, it is brand new and has only been discounted due to being produced using the previous years material.