SDG I-Sky I-Beam Saddles: The I-SKY line uses the same proven shape as the popular F-Style, but instead of oversized rails the I-Sky uses SDG’s patented I-Beam System, which utilizes the latest DuPont® nylon fiber composite material to create an extremely light and unbelievably strong saddle. The I-Beam system enables top pros like Aaron Chase, Eric Porter and Kyle Ebbett to eliminate bent rails and shed a significant amount of weight from their ride.