SLR Boost's compact shape provides the perfect combination of comfort and performance Fibratek is Selle Italia's latest cover material offering supreme durability SuperFlow features a large anatomic central relief area which allows rider to sit comfortably and pedal efficiently Carbon Rails Become an idmatch dealer to fit the correct saddle to your customer. 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)