SuperFlow features a large anatomic central relief area which allows rider to sit comfortably and pedal efficiently- Fibra-tek: Selle Italia's latest cover material offering supreme durability and comfort- Carbon Rails- For more information on idmatch visit http://www.selleitalia.com/en/idmatchsystem/- L3: "Wide" intertrochanteric distance and high pelvic rotation (Flow and SuperFlow saddles)- S3: "Narrow" intertrochanteric distance and high pelvic rotation (Flow and SuperFlow saddles)