The S-Shaped cross-sectional design, presenting lower mass percentage than a conventional cross-section, is advantageous in reducing torsional stresses because of the less surface in contact with the canal walls, presents less blade engagement compared to the conventional cross-section, which can influence the instrument cyclic fatigue resistance. Of those that allow AF BLUE S ONE with extreme flexibility and better flexural resistance. 1 Adopted the latest tech - Nano-Ceramic Layer, and given in addition the bright blue color, represents the smooth surface, which optimize a lower fatigue accumulation and increase root canal instrumentation safety.