Performance Posture 3 for pelvic rotation with a balance of comfort and efficiency;Channel Flex on the bottom of the shell for added compliance;Zone Density shell construction is strategically placed for optimal comfort and performance;Size-Specific Curvature ensures that each saddle is designed specific to its width;Oversize carbon rails for the ultimate in lightweight strength;inForm BioDynamic products optimise your natural movement for sustained, higher performance;Requires oversize rail-compatible seatpost and 7x10 mm seatpost ears;